THE DANISH INGOLF-EXPEDITION. VOL. VI, PART 2. CONTENTS: WILL. LUND BECK: DESM ACID ONI D/K (PARS.). ^^^ ^= ^^ CO ^^^■^ m — = LT) = r^ o * rH I i-n <^— - D ^1 ^= D m D m ^^^ ^== D M_^^^ S^^ZZ o — _ PUBLISHED AT THE COST OE THE GOVERNMENT BY THE DIRECTION OF THE ZOOLOGICAL MUSEUM UK THE UNIVERSITY'. • c -^aMAsy~'— COPENHAGEN. H. HAGERUP. PRINTED HV BIANCO LUND. 1905. THE DANISH INGOLF-EXPEDITION. VOLUME VI. 2. PORIFERA. (PART II.) DESMACIDONID/E (PARS.). BY WILL. LUNDBECK. WITH 20 PLATES AND 7 FIGURES IN THE TEXT. TRANSLATED BY TORBEN LUNDBECK. ->4H2Xf<- COPENHAGEN. PRINTED BY BIANCO LUNO. 1905. Ready from the Press October the 5 th 1905. CONTENTS. Desmacidonidse. Introduction Desmaeidonidse. Mycalinae Page r 7 7 Mycaleae 7 Esperiopsis 7 villosa Cart 9 Normani Bow 13 sp. (?Alderi Bow.) 15 pedicellata n. sp. . , 16. forcipula n. sp 17 flagellum n. sp 20. typichela n. sp 22 Mycale 23 — placoides Cart 24 — lingua Bow 29 — ovulum O. Schmidt 34. thaumatochela n. sp 39, — titubans O. Schmidt 41 — intermedia O. Schmidt 43 Asbestopluma 43 Asbestopluma s. str 44 pennatula O. Schmidt 44. bihamatifera Cart 51 furcata n. sp 54 Lycopodina n. subg 58 cupressiformis Cart. 58 lycopodium Levins. 62 hydra n. sp 66, Cotylina n. subg 68 infundibulum Levins 68 comata n. sp 72 Cladorhiza M. Sars 78 abyssicola M. Sars 79 gelida n. sp S3 tenuisigma n. sp 87 iniquidentata n. sp 91 corticocancellata Cart 93 oxeata n. sp 97 Chondrocladia 102 gigantea Arm. Hans. 102 Artemisina no arcigera O. Schmidt no. apollinis Ridley and Dendy 114 Homoeodictya 117 flabelliformis Arm. Hans. 118, palmata Johnst. 121 Page Mvxillete 125 Dendoricella 126, rhophaluni n. sp 127 obesichela n. sp 130, Myxilla 131 — incrustans Johnst 132 rosacea Lieberk 138 fimbriata Bow 141 brunnea Arm. Hans 144 — perspinosa 11. sp 147 pedunculata n. sp 148. diversiancorata n. sp 150, — pluridentata n. sp 151 Lissodeudoryx 153 lobosa n. sp 154, Sophia Frstdt 1 56. fragilis Frstdt 158 diversichela n. sp 160. indistincta Frstdt 162 complicata Arm. Hans 166. vicina n. sp 169 stipitata n. sp 170. Iophon 173 piceus Vosm 175 dubius Arm. Hans 180. frigidus 11. sp 183 Iotrochota 1S5 varideus n. sp 185 oxeata n. sp 1 86 abyssi Cart 1S8. dubia n. sp 189, intermedia n. sp 190, rotulancora n. sp 191 polydentata n. sp 192 affinis 11. sp 194 spinosa n. sp 195. Forcepia 198 — forcipis Bow 198 fabricans O. Schmidt 201 — Topsentii n. sp . . . 204 — Thielei n. sp 206, groenlandica Frstdt 209. Melonanchora Cart 211 elliptica Cart 211 emphysema O. Schmidt 216 4 1 8 s r Porifera. II. By William Lundbeck. THE present work, as shown by the title, is a direct continuation of my work, « Porifera, Part I, The Danish Ingolf-Expedition, VI, i, published in 1902. In the introduction to this first part I rendered an account of the material and of the geographical territory treated in the work. Since that time some new material from the territory has been added, and this material has been included in the work. The new material has especially been gathered by the surveying vessels the «Diaua» and Beskytteren > stationed at Iceland and the Faroe Islands, on the cruise of the «Thor», the steamer of the international investigation of the sea, in 1903 under the direction of Dr. Joh. Schmidt, aud more particularly must be mentioned the very considerable material collected by Dr. A. Appellof and cand. mag. Ad. Jensen during the cruise of the Michael Sars in 1902 under the direction of Dr. Hjort. In the first part of the work the families Homorrhaphida and HetcrorrhaphidcE of the sub-order Haliclwndrince were treated. The present part comprises part of the family. Desmacidonidce. Partly tollowing Topsent I divide this family into the subfamilies Mycalincc (= Esperellince olim) and Ecty- onincB; Mycalinm I divide into two groups Mycalea and Myxillea (the latter corresponding to the subfamily Dendoricinm of Topsent). I regard these two divisions as groups of one subfamily, as I think them more closely allied to each other than to Ectyonina, at all events when the question is of the typical forms of this sub-family. On the other hand, several genera of EctyonincB are assuredly closely allied to genera of the group Myxillecv. The systematism of the sponges is still in main- respects groping its way, aud such is also the fact inside the family Desmacidonidce. The separation into the two subfamilies Mycalincr and EctyonincB is scarcely a quite natural one, in the way in which it is made at present, being chiefly based on the occurrence of special, socalled accessory spicules in the latter subfamily. Thus the dermal spicules with equal ends characteristic of the Myxillcce, occur also in some Ectyo/u'ncz-genera; the accessory acanthostyles are often very scarce, or the acanthostyles of the species are so very varying in size, that it is difficult to decide whether two separate groups of sizes are present. The decision is especially difficult in incrusting forms, where the character of the accessory styles jutting out from the fibres is wanting, all the styles being basal. A particular fact is also the occurrence of parallel, corresponding genera in the two subfamilies; thus Myxilla (--= The Ingolf-Expedition. VI. 2. I PORIFERA. II. Dendoryx olim) corresponds to the Eciyomn-genus formerly known by the name of Myxilla, Iophon to Pocillon, Iotrochota to Hymetrochota , Grayella (= Yvesia Tops.) to Pytheas, and Tedania to Acheli- derma; also these facts seem to tell against the naturalness of the system. It; is therefore rather prob- able that the division into Mycalince and Ectyonince will have to be abandoned or altered, as has already been advanced by Ridley and Dendy (Challeng. Report, Monaxonidse, 129), at the same time as they reduce Carter's family Ectyonid® to a subfamily, and as will also be mentioned in several places of the present work. I have, however, not yet ventured to abandon this division, as my investigations have not hitherto shown me a more natural way of grouping. For the present the efforts must be directed towards a thorough examination of genera and species, as this will to a high degree facilitate the natural grouping with regard to the higher divisions. In the introduction to the first part I have spoken of several descriptive terms and their use, to which I mav here refer. The terminology of the spicules is the same with regard to megasclera and to the forms of microsclera occurring in Heterorrhaphidcc. In the family Dcsmacidonidce, however, we meet new forms of microsclera belonging to the socalled chelate type, and it will be necessary to premise some remarks on the two principal forms of this type Chelae and Ancorae. The spicules belonging to these forms are at this moment by all authors with the exception of Levinsen comprised under the name of chelae. This name was proposed in 1887 by Ridley and Dendy in Challeng. Rep., and this proposal was of some importance, as up to that time there had been no established term, but terms as anchorates», < Haken , Anker a. s. o. had been used by the different authors. While Schmidt and Carter upon the whole have given good figures of these bodies, Bowerbank on the other hand was highly misled with regard to their forms; even Carter has in 1871 (Ann. Mag. Nat Hist. 4 th ser. VII, 277) pointed out this fact, but Levinsen and after him Ridley and Dendy have rendered a more particular account of it. Levinsen especially Was he, who first and clearly showed (Dijmphna-Togtets zool.-bot. Udbytte, 1887, 354) that Bowerbank gener- ally figures the chelae in two positions, from before and from the side, and interprets these figures as two different forms. Another common mistake, that the tooth of the chela has not been seen, may be found in many works down to the present time; when this is the case the chela is figured with a plate in each end, but without a tooth; or only the tuberculum has been seen and interpreted as forming a small short tooth. This mistake is easily accounted for, as the tooth is often so thin, that it can only be seen under high magnifying powers and by proper light. In this respect Ridley and Dendy 's Monaxonidse (Challeng. Rep.) occupies a high position by its excellent figures of the chelae. Otherwise the mistake is a common one; thus in the works by Vosmaer on the sponges of the Willem Barent -Expedition it is found throughout, and this holds also quite good of his work on the sponges in Bronn's Klassen und Ordnungen, where almost all the figures of chelae are erroneous, no corresponding forms being found in nature. In a paper by Vosmaer and Pekelharing from 1898 (Verhaudl. der Kon. Akad. van Wetensch. to Amsterdam, 2, IV, no. 3, 32) entitled On Auisochelae PORIFERA. II. 3 and Isochelse--, and in which therefore a thorough examination of these features might be expected, we find nevertheless that on PI. II, fig. 9, and especially fig. 11, which latter represents an almost grown (rather a quite grown) chela, no tooth has been drawn in the smaller end. Also in Topsent's other- wise excellent works too little attention has been paid to the study of the chelae; in his work from 1892 (Resultats des Campagn. scient. du Prince de Monaco, Fasc. II) the chelae are shown in very small figures, aud most frequently the tooth has not been figured. In the work on the sponges of the Belgic Antarctic Expedition from 1902 (Voyage du S. Y. Belgica, Spongiaires) the case is somewhat similar; thus the tooth is not drawn on the chela seen from the front, PI. Ill, fig. 9 b. Even in the fine work from 1904 (Resultats des Campagn. scient. du Prince de Monaco, Fasc. XXV) errors of this kind are found; thus the chela; on PI. XIV, fig. 15 e, fig. 18 d, and PI. XV, fig. 20, are drawn without the tooth, while others, especially the larger ones, are drawn correctly. As mentioned above, all these forms are generally comprised under the name of cheke, and are regarded as being principally of the same kind. In contradistinction to this view Levin sen in 1893 (Vidensk. Medd. fra den Nat. For. Kobenhavn 1893, 1) has advanced a new view, dividing these bodies into two principally different forms and giving to these the respective names of chelae and ancorae. The difference between these two forms is briefly, that chelae have only one free tooth and besides more or less broad lateral alae on the shaft, while ancorae have more, 3 — 7 free, uniform teeth besides lateral alae on the shaft. Levinsen regards the teeth in both forms as bendings of the axis. Carter and Ridley aud Dendy regard the lateral teeth in aucorte and the alae in chelae as formations of the same kind, and are most inclined to regard the lateral teeth in ancorae as developed by the alae of a chela being split of from the shaft. Vosmaer and Pekelharing in the above quoted paper from 1898 attack the interpretation of Levinsen, and declare that the teeth of the ancorae cannot be interpreted as bendings of the axis, as long as an axial canal has not been made out in all the teeth of the ancorae, and if these teeth are formed by the axis being bent and split in several branches, then a sponge with such spicules would not belong to the Monaxonidae. The authors think it most probable that the ancorae have arisen by a splitting of the tooth of the chela. To these different theories it is only to be remarked that it may be regarded as a fact that chelae and ancorae are allied bodies, but that it cannot at present be decided, in what way one form may be thought to have arisen from the other. Now it is certain that in a few chelae we may meet with a feature which is probably a splitting of the tooth, as in some Asbrs/oJ>lu///a-species in the smaller end of the chela, and in the present work in the genus Myxilla instances will be shown of ancorae with at all events a beginning splitting of teeth; but at present it is impossible to decide how this fact is to be interpreted. On the other hand it is certain that the two forms, as they now occur, are principally different: in one form, chelae, only one tooth is found and alae on the shaft, in the other form, ancorae, several quite homologous teeth are always found as well as alae on the shaft. Transitional forms have not been found hitherto, and when Ridley and Dendy say (Challeng. Rep. Monaxonida, XIX): Numberless gradations exist between these two types , this is not correct; their view arises from the fact, that they put ancorae and chelae arcuatae together in one group in contra- distinction to chelae palmatae, but even from this point of view the statement is not correct. The objection of Vosmaer and Pekelharing, that the ancorae, if the representation of Levinsen is PORIFERA. II. correct, would be polyaxial spicules, seems to me to be of no importance, as the question might very well be of a secondary splitting of the axis of the original monactinal spicule. Otherwise I shall remark that it may be proved that the tooth of the chela can be traced back to a bent axial part, while the teeth of the aucorse, in spite of the fact that their form quite corresponds to that of the tooth of the chela, are, perhaps, not axial bendings, but are formations which have, all of them, also the middle tooth, arisen in another way, through growth by apposition. I cannot, however, at present establish this as a sure fact. If it should prove correct, Levinsen of course is not right in designating the teeth of aucorse as axial bendings, but the principal difference between chela; and ancorae will then be still greater. In this connection it may be well to remind of the fact that ancorae may be found provided with an even number of teeth, without any middle tooth. Besides the division into chelae and ancorse Levinsen, in the paper quoted, subdivides chela; into two forms, chelae palmata; and arcuatse. The former have a straight, or most frequently only slightly curved shaft, and rather large alae forming together an almost triangular or oval plate, often with a deep notch below; the tooth is often rather broad. In the other form, chelae arcuatse, the shaft is most frequently rather strongly curved, the alse are highly indented below and only attached to the shaft for a comparatively short way, thereby getting a somewhat tooth-like appearance; the tooth is most frequently rather narrow. To be sure, these two forms are not principally different, but differ only in form, and forms may also be met with that may only with difficulty be referred to either of them; but generally they form two well-marked groups, and are also characteristic for certain genera. Therefore there is every reason to keep this division. By all the authors who acknowledge only one form, chelae, these are generally described as «tridentate=> or .palmate . This division is a complete mistake; the forms called « palmate > are gener- allv chelae palmata;, but in the term «tridentate> are comprised both chelae arcuatse and ancorse. Thus Ridley and Dendy and Topsent use generally these terms; nay, in Topseut's work on the sponges of the Belgic Antarctic expedition we even meet again the old term bidente». Under Des- macidon setifer it is said in the text of the chelse «dentes ou palmes >, and on PI. Ill, fig. 6 a series is figured of which it is said in the explanation of the figures, «a, b, formes rudimentaires» ; this is cor- rect, the figures show two developmental forms; then the continuation runs, *c, isochele palme, d, iso- chele dente, c', d', formes intermediates >. All the figures belong to one form, a typical palmate chela, c is seen from the front, d from the side, while c' and d' are two a little contort specimens, and one end is therefore seen a little from the front, the other a little from the side. Besides the division made by Levinsen of the forms belonging here, I further divide ancorae into two classes which I call ancorse spatuliferae and unguiferae. In the first form the shaft is most frequently straight or slightly curved, and the teeth are comparatively large and broad; their number is very frequently three, but there may be more. In ancorae unguiferae the shaft is most frequently more curved, the teeth are comparatively small and pointed, their number is three to nine, generally more than three. These two forms of ancorse are only different in form, and transitional forms occur, but the two forms are most frequently well-marked and characteristic of particular genera. In the palmate chelae the ends may be either like or unlike each other, and according to this they are either isochelse or anisochelse; in the arcuate chelae, the ends, as far as known, are always PORII-ERA. II. like, and accordingly they are isochelae. In ancorse spatuliferae the ends, as far as known, are always like, they are isancorae, while ancorse unguiferae may be isancorae or anisancorae. According to the preceding the chelate microsclera may be divided into the following forms: Cheke palmatse arcuatae aniso- iso- Ancorse spatuliferae unguiferae most frequently 3—9 teeth 3 teeth 1S0- 1SO- amso- AU forms of microscleres belonging here may always be referred to one of the types chelae or ancorae. This does not seem to be generally acknowledged. Thus the small chelae characteristic of the genus Asbesiopluma have given rise to different interpretations, but in reality they are constructed on the same principle as the other chelae. Even so deviating a form as the chela in Mycale thauma- tochelcE described below is of the same fundamental structure, and this holds good also with regard to the peculiar wry chela in M. Utubans; nay, even the bipocilla in the genera lophoti and Pocillon may be referred to the same form. Top sent (1 c. fasc. XXV, 209) proposes the term placocheles> for the peculiar palmate isochelae in Gziitarra and Esperiopsis villosa; I cannot, however, see any reason for a special name for these forms, as they are typical isochelae palmatae. A typical chela thus con- sists of the following parts, which I designate by the following terms, generally in use: a shaft or an axis having in either end a bending, the tooth, and at either end two lateral extensions, the alae; between the shaft and the tooth, at a right angle to these, is found a plate-shaped part, falx, and the thickened part of this structure shining through the fore side of the tooth, is called tuberculum. In ancorae quite the same parts are found, the only difference being that in these several teeth are found each with falx and tuberculum. With regard to the development of these forms many misconceptions have been advanced. As early as in 1857 Bowerbank (Phil. Trans. Roy. Soc. London CXLVIII, 304) and later in the first volume of Monograph 1864, 47, PI. VI, fig. 144— 147, has given a description with figures of these forms, which, to be sure, is not correct, but nevertheless rather good and free of the misconceptions arising later, as he has clearly understood that the first beginning was of the same length as the fully developed spicule. Also O. Schmidt in 1862 (Die Spong. des adriat. Meer., 8), although he does not understand the growth of these spicules, has seen that small and large chelae occurring in the same sponge are not stages of growth of the same form. Later the misconceptions appear. Carter, in 1874 (Ann. Mag. Nat. Hist. 4, XIV, 100), advances the view that the anisochelae begin as isochelae; he has been led to this view by the fact that he upon the whole regards small isochelae, in a species also provided with large chelae, as younger stages of these, and so he is led to suppose a growth with the most peculiar alterations of form. That Carter has not later been quite sure of the correct- ness of his theory may be seen from the fact that in 1882 (Ann. Mag. Nat. Hist. 5, IX, 298) where he 6 PORIFERA. II. mentions small isocheles occurring together with large auisocheles, he says: and therefore the inequi- anchorate may possibly begin its development in this form (i. e. as isochela), and he continues, how- ever it does not occur in the ovular embryo of Esflcria, while the inequianchorate do. Ridley and Dendv, in Challeug. Monaxonida, follow Carter completely, though they have followed the develop- ment of anisochelse in E. mammiformis. They still regard the small chelae as developmental forms of the large ones in the same spouge, either the question is of isochelse or anisochelse; in several places however, they say possibly young forms . Levi us en, in his paper from 1893, gives an exhaustive description of the growth of the chelse. In the introduction to part I of the present work I expressed the opinion that in this second part I should be able to corroborate his examinations with regard to a great number of forms, and this is also the case. In the descriptions of the separate species this fact will be more particularly mentioned. Here, as in the other spicules, the growth takes place exclusively by apposition, either simple apposition, or after fixed lines, and the younger forms must always be inscribable in the older ones. The chelae and ancora: therefore begin as axes of the full, or about the full length; in the chela; the beginning is a straight or curved staff with shorter or longer axial bendings in either end, and tooth and alse arise gradually and grow to their full size. In the ancorae the growth takes place in a similar way, but their teeth, as before mentioned, are perhaps not axial bendings, but arise in another way. Vosmaer and Pekelharing, in their paper from 1898 quoted several times in the preceding, treat and figure the development of the anisochela in M. syrinx, but their discussion contains nothing new. When they conclude, on account of their having found chelse that were a little contort, we have therefore the right to say that chelae not only can be derived from spicula which have the shape of C, but indeed from spicula known as sigmata , this conclusion is unwarranted; developmental forms of the chelse are in no instance sigmata, and may always easilv be distinguished from these; the fact that chelse may be contort, a feature that is much more frequent and mav take place to a much higher degree than seems to be known by the authors, proves nothing at all. Developmental forms of the chelse have not rarely been misinterpreted. I shall here state the cases I have found. Carter (Ann. Mag. Nat. Hist. 5, IX, PI. XI, fig. 17 d and h) calls these two figures with a querv bihamates ; they are developmental forms of an anisochela. He calls (ibid. 5, XV. PI. IV) fig. 3 d bihamate-like spicule ; it is the developmental form of an arcuate chela. Fristedt (Kgl. Sv. Vet. Akad. Handl. 21, no. 6, Tab. Ill) calls fig. 3 h spiculum c-curvato-obtusum , but regards it with a query as an undeveloped chela; it is an undeveloped arcuate chela. La nib e (Trans, of the Roy. Soc. of Canada, XI, sect. IV, PI. II) calls fig. 4 c a sigma; it is a developmental stage of a palmate anisochela. Levin sen, in his paper from 1893 several times quoted above, after having established the fundamental difference between chelse and ancorse, and rendered an account of the fact that they are never found together, expresses the opinion that this fact must involve the alteration in the system that species with chelse and species with ancorse cannot be kept in one genus. I can fully agree with this view, and therefore in the present work I have separated the species according to it. In this I'ORIFERA. II. respect the question is for the present only of the genera Myxilla—Lissodcudoryx and Desmacidon- Homoeodictya; the particulars will be found under these genera. With regard to the examination I shall only add the further remarks that the examination of the structure of the skeleton has generally been made on dried preparations placed in xylol in not too thin sections, by which means distinct and complete views of the skeleton are obtained. Care must be taken, of course, that the skeleton is not distorted by the drying. I mention this proceeding, because I think it gives a better and more distinct view than is got when the sponge is cut in a moist state, and by the use of my descriptions of the skeletal structure it must be remembered that they are made from such preparations. For the examination of the structure of the spicules I have generally used Canada balsam-preparations; in a few cases I used Naphtalin-a-monobromatum, which proved to be very good when the question was of very thin silicious plates; also a mixture of Naph- talin-a-monobromatum with Canada balsam was in some cases found to be good. Storax resolved in benzol and alcohol has been used in a few cases; but in by far most cases Canada balsam proved very efficient; when the spicules are completely cleaned, it will in balsam-preparations almost always be possible to study the structure to the finest details. Fam. III. Desmacidonidae. Subfam. i. Mycalinae. Group, i. Mycaleae. According to what has been shown by Thiele (Abhandl. der Senckenberg. nat. Gesellsch. XXV, 949) the name of Esperella Vosm. must be altered to Mycale Gray, and consequently the name of the subfamily and the group will also have to be altered. Esperiopsis Carter. The form varying ; in crusting or irregularly solid, but frequently erect and Icuf-shaped, or in other xvays symmetrical. The skeleton may be constructed in various ways; in the erect forms it may consist of long, well developed and branched fibres, but in the solid forms and in the iuerustiug ones it rets a halichondroid or renicrid structure. Spongin is most frequently present . the amount varying. Spi- cula '■: Megasclera monactinal, styli or subtylostyli; microsclera; the characteristic microsclera are isochelce palmatce, which may occtir in one or several forms ; to these may be added isochelce arena fee, sigmata of one or more forms, foxa, or forcipes in different combinations. The genus Esperiopsis was establised by Carter in 1882 (Ann. Mag. Nat. Hist. 5, IX, 296) for the species villosa, which he had originally referred to Espcria. The distinctive character of the genus is the fact that the characteristic microsclera are isochelse, which was also the principal reason why Carter separated the species into a particular genus; to be sure he mentions also some other features, but they are of no consequence. Levinseu (Studier over Svampe-Spicula: Cheler og Ankere; Vidensk. .s PORIFERA. II. Medd. nat. For. Kobenhavn for 1893.1894, 11) says that there is no reason to keep the genus, as in the old genus Mycale (Esperclla olim) we have now exclusively anisochelse, now exclusively isochelee, and sometimes a mixture of both, and as the difference between an isochela and an anisochela may be very slight. I think, however, that there is good reason for keeping the genus, as the characteristic micro- sclera in Mycale are anisochelae, and small isochelse seem to be of very rare occurrence in this genus. Carter (1. c. 298) mentions this fact in a general way as occurring in some Mycale-species , among which he only mentions M.plumosa Cart., aud Ridley and Dendy (Chall. Rep. XX, 65) state it with regard to M. parishii Bow. in which species the small isochela is of a particular structure 1 ). With regard to the other objection made by Levin sen to the keeping of the genus it is to be said that the anisochela;, to be sure, may approach isochelse as to form, but no species is known, however, with regard to which there can be any doubt in this respect. The Mycale-species most closely allied to Esperiopsis, and more particularly to the Esperiopsis-species with renierid skeletal structure, is perhaps Mycale ovitlum O. S., in which some of the anisochelae may show only slight difference as to the size of their ends, but the ends however are never of quite the same size. Another question is whether all the species for the present referred to Esperiopsis, are naturally closely allied. The species show great difference, as well with regard to form as to skeletal structure; also the combination of microsclera is varying to some degree, and rather many different forms may occur. To get a general view I shall put together, as far as possible, the described species with a statement of their microsclera; with regard to the species of Bower bank I follow, with a few excep- tions, the interpretations of Topsent (Revue Biol, du Nord de la France, VII). E. (Isodictya) Edwardii B Isochelae palmatae. - ( — ) Normani B — - ( 1 fucoruin Johust - ( — ) Alderi B - ( — ) scitula B - f — ) involuta B — - ( — J hispida B — ? - (Halichondria) co/upressa B — ? - / I Thompsoiii B - ( Antpliilectus) hispidula Ridley - Challengeri R. and D - profunda R. and D - anomala R. and D — - columnata Tops — - rigida Lambe — ') Carter, as is well known, thought these small isochela? to be developmental phases of the anisochelae. He puts forth this theory in 1874 (Ann. Mag. Nat. Hist., 4, XIV, 102), and here he figures for M. aegagropila Johnst. the typical aniso- chela, as also some small bodies situated in cells, which bodies he interprets as isochelate developmental phases of the aniso- chela. Levinsen (I.e. 9) has been of opinion that the question was here of small arcuate chelae. As there is, however, every reason to suppose that Carter has really had before him M. aegagropila (he mentions one of Johnston's original specimens), and as in this species no small isochelae are found, it is not possible to decide, what Carter has seen, and his figures are not to be explained. Developmental phases of anisochelae thev cannot be, as those have a quite different appearance. PORIFERA. II. E. vancouverensis Lambe .... Isochelae palmatae. - quatsinoensis Lambe - laxa Lambe - rugosa Thiele — - pedicellata mihi — - (Isodictya) collina B sigmata. ? - (Halichondria) rigida B. . . . Isochelae, sigmata. (If this species proves to be an Esperiopsis, rigida Lambe will have to change its name). - cylindrica R. and D Isochelae palmatae, ?toxa. - symmetrica R. and D sigmata of two forms. - typichela mihi — of two forms. - pulchella R. and D — of two forms, isochelae arcnatae. - prcedita Tops isochelae arcnatoe, sigmata. - vittosa Cart of three forms, sigmata. - flagellavi mihi of two forms, sigmata, sigmata flagellata. - decora Tops of three forms, - forcipula mihi isochelae arcuatae, sigmata, forcipes. - polymorpha Tops Isochelae arcuatae, sigmata of two forms, toxa (small, sharply bent). - Schmidlii Arnesen — sigmata. - glomeris Tops ? - (Holopsamma) turbo Cart. . Isochelae. Dendy, after having found isochelae in this very deviating form, refers it to Esperiopsis. Halichondria folia ta Bow., which Topsent, in the mentioned work, refers to Esperiopsis, is an Echinoclathria; the same holds good of Esperia foliata Frstdt. In the generic diagnosis I have given as characteristic microsclera isochelae palmatae; as will be seen, three species deviate from this rule, viz. polymorpha Tops., Schmidlii Arnesen, and glomeris Tops, which have, as to chelae, only isochelae arcuatae, which seem to be of quite typical form. As above mentioned, however, the difference between chelae palmatae and arcuatae is not quite sharp, and per- haps it will be necessary only to say that the characteristic microsclera of the genus are isochelae. I shall still add that Kieschnick (Semon: Zool. Forschuugsreisen in Austral. Band V, Denkschrift. Med. Nat. Gesellsch. Jena, Band 8, 1900, 572, Taf. XLIV, Fig. 12, Taf. XLV, Fig. 51—52) has established a species, £. viridis. As the other species mentioned in this quite useless work it is unrecognizable, but it seems most nearly to be a Chondrocladia-species. Of microsclera are mentioned isochelae with six teeth (the very bad figure shows seven), and smaller isochelae with five teeth (to which a quite useless figure). r. E. villosa Cart. PL I, Fig. 4. PI. VIII, Fig. 1 a— i. 1874. Esperia villosa Carter, Ann. Mag. Nat. Hist. Ser. 4, XIV, 213, PI. XIII, figs. 13—15, PI. XV, fig. 36. 1879 Unknown sponge Carter, Journ. of the Roy. Micr. Soc. II, 502, PI. XVII a, fig. 12 a, b, c. 1882. Esperiopsis villosa Carter, Ann. Mag. Nat. Hist. Ser. 5, IX, 296. The Ingolf-Expedition, VI. 2. 2 IO PORIFERA. II. 1887. Esperia villosa Fristedt, Vega-Exp. vetensk. Iakttag. IV, 451, PI. 25, figs. 33 — 39, PI. 29, fig. 19. 1904. Esperiopsis villosa Topsent, Resultats des Camp. Scient. dn Prince de Monaco, Fasc. XXV, 211, PI. XVII, fig. 2 a— c. Erect, more or less irregularly leaf-shaped. The surface finely shaggy from projecting spicules ; the dermal membrane thin, with no separate skeleton, resting on spicules that are spread in a peni- cillate way. Oscula formed as small, conical projections, along the upper edge or a little down on the surface. The skeleton consists of polyspicular fibres branching up through the sponge and anastomosing; from this skeleton shorter fibres go off to the surface. Spicula : Megasclera styli or slightly -marked sub- tvlostyli o-6 — o-/j'" m ; tuicrosclcra of four forms : isochchr pabnatcr of three forms, large ones of a parti- cular narrow form 0-08 — o-/2""". middle ones o- 078—0-092""", small ones 0-021 — o-oji mm ; sigmata, large 0-045 — o-ig""". This species has been pretty well described by Carter with the only misconception of the mutual relation of the three different chelae, which is a consequence of his wrong interpretation of the growth and development of these bodies. The species seems most frequently or always to be erect and more or less leaf-shaped, but is otherwise of somewhat varying form and thickness, and frequently of an irregular appearance. With its base it is fastened to stones or some other underlayer, and most frequently its base is widely spread. The largest specimen in hand is of a height of ca. i3 c,n and a thickness of about 15 — 20 mm . The colour (in spirit) is generally gray, sometimes passing a little into brownish. On account of its skeleton the sponge is rather firm, but may, however, be torn easily, and all the specimens are much damaged. The surface is finely shaggy on account of the projecting spicules. The dermal membrane is thin, with no skeleton, supported by spicules projecting in a fanshaped way. The pores are situated in the dermal membrane between the projecting spicules; sometimes they are very close-set, so that the membrane becomes a network. They are round to oval, and their size is generally between 0-02 and o - i5 mm . Oscula are constructed in a peculiar way; along the upper edge of the sponge, or sometimes a little down on the surface is found a number of projections quite slightly conical ; they are of an average height of a few mm., and have a diameter not exceeding i mm . They consist of spicules and are apparently solid, but when cut off at the base they leave a hole, and are seen to be hollow in their lower part; in a few of them a little opening is also found in the top. All the oscula (they are only found distinctly in the best preserved specimen) may be supposed to be shut, open oscula were not seen. Further down on the sponge a few round holes are seen, which I take, however, to be due to damaging 1 ). From the osculum a canal may generally be traced some way down in the sponge. The skeleton consists of irregularly branched, polyspicular fibres, branching from the base up through the sponge, and frequently anastomosing. They are thickest in the lower part of the sponge; in the middle of the sponge they have an average thickness of ca. o - 35 mm ; they are polyspicular, and have a great number of spicules side by side. The fibres with their anastomoses form a rather dense and solid skeleton. From this skeleton close-set fibres go off to the surface generally curving some- what upwards. These fibres divide on the way to the surface, and pierce the dermal membrane as ') When Carter (I.e. 1874) says: ^Vents scattered here and there irregularly', it is presumably owing to the fact that his specimen has been damaged, and the real oscula have been wanting or indistinct. PORIKERA. II. II bundles of spicules spread in a more or less fan-like or penicillate way; the fibres are generally of a length of 3— 4 mm . The dermal membrane is supported by the projecting bundles of spicules, and is provided with no skeleton of its own. The fibres and bundles of spicules that support it, are, however, often far from being perpendicular on the surface, and accordingly, when a piece of the skin is viewed under the microscope, it may appear, as if there was a reticulation in the skin, the fibres under it being also seen. In the fibres of the skeleton some spougin is seen, which, although not abundant, coats the fibres completely. As mentioned above the fibres are thickest at the base of the sponge, and the spongin is also most distinct here. Below the fibres pass into a thin basal membrane formed by spongin, and provided with scattered spicules; it is directly fastened to the substratum, from which it is easily separated, and then it shows a smooth surface. Spicula; a. Mcgasclcra are styli or very slightly marked subtylostyli; most frequently they are straight, sometimes quite slightly curved. They are thickest in the middle, and thus a little fusiform, the greatest thickness being not rarely nearest to the pointed end. The point is evenly tapering, but not long. Most frequently they are slightly restricted a little below the rounded end, and thus ap- proaching to subtylostyli, but the restriction is not rarely imperceptible or wanting. The length is between o-6— o75 mm , most frequently approaching the latter size; sometimes it may go down to o-5' n[ ". The thickness is between ca. croi— o-02 m,n . Finer spicules, developmental forms, occur, but in very small number. The specimen described by Topsent I.e. has somewhat larger megasclera; they are stated to be 0-935— o-o,8o mm . b. Microsclera : Of these are found isochelae palmatse of three different forms, and sigmata. 1. The largest chelae are of a peculiar shape, Carter calls them weaver's shuttle- like »; they are narrow, the side-edges of the two alae are parallel, and the alae continue far down along the shaft, so that only a short space is left in the middle where the cylindric form of the shaft is seen. The shaft is straight. The side-edges of the tooth are likewise about parallel, or slightly converging towards the end, and the end of the tooth is rounded. When the tooth is seen from the front, it appears to have a thickened edge, but this is owing to the fact that the sides are curved inwards. When the chela is viewed from the side, it is seen that as well the sides of the tooth as the alae on the shaft are curved inward so as to meet each other at the ends of the chela. Seen from the side the tooth most frequently bends a little outward at the end, while the outermost point is again bent inward in a claw-like way; the latter bend, however, is in so far only apparent, as it is owing to the bending in of the edge. The edge of the tooth being thus bent inward all round the tooth becomes hollow on the inward side. The tooth is generally of about the same length as the alae, and its position is about parallel to the shaft. At its basal end the axis is seen as a little oval tubercle. These chelae are sometimes somewhat twisted. The length is rather varying, from 0-08— o-i2" ,m , and the greatest breadth, a little above the middle of the tooth, is ca. o-oi3' nm . Of these chelae developmental forms are found; the youngest stage observed was formed as a fine staff having at both ends a large part recurved with a round curve, and the recurved ends were finely tapering (PI. VIII, fig. id). This staff thus represented the axis of the chela, alae and tooth having not yet been formed; the development now consists only in the growing forth of the alae and the tooth. The develop- mental forms have the full length of the chela, the youngest stage was thus measured to o-i ram . 2. The middle form of chelae is somewhat smaller and broader; also in these the shaft is straight 12 PORII-KRA. II. or about straight. The alse do not continue so far down the shaft, so that the free middle part of the shaft is about one third of the whole length or thereabout. The lateral edges of as well the alse as the tooth diverge towards the middle of the chela, the terminal parts of which thus get a triangular form. The lateral edges of both the alse and the tooth curve inward, and thus the alse and the tooth turn concave sides towards each other. The tooth is generally a little narrower than the alse together, and sometimes of the same length, sometimes a little shorter; it forms an acute angle with the shaft. The tuberculum is longish, and a rather inconsiderable falx is found. This chela may vary somewhat as to form, especially with regard to the breadth of the alse and the tooth, and the length of the middle part of the shaft; also the end of the tooth may be differently rounded, and the lower edge of the alse may join the shaft at a right angle or with an even curve. The length is generally between 0-078 and o-092 mm , but a few smaller ones occur, down to o-05 mm . The greatest breadth is most frequently 0021 — o - o28 mm , but much narrower forms may be found. Also of this chela a few developmental forms were found; they are very like those of the preceding form, from which they may be especially distinguished by the fact that a falx is begun at an earl}' stage. The incipient alse are as to form somewhat different from the fully developed ones (PL VIII, fig. 1 f|, but the final form is reached through mere apposition. 3. The third form of chelse is considerably smaller than the pre- ceding ones; these chelse are of a form similar to that of the middle ones, but their shaft is somewhat curved; the breadth of the teeth is the same as that of the alse taken together. The length is between . 02I mm anc i o^i™'", only rarely towards the latter length, the breadth is 0-0057 — o-oo7 mm . A few chelee may be found, seeming by their size and by having only a slightly curved shaft to form a transition between the two latter forms. Carter, as may be seen from his description and figures, has seen all three forms of chelse, but on account of his interpretation of the growth of the chelse he has taken the smallest and middle forms to be developmental stages of the largest form. What Topsent I.e. says of the largest chela?: Pour realiser leur form, ces isocheles subissent une atropine a pen pres complete de leur dents laterales» is not correct; these chelse, as the other chelse in the sponge, and as all palmate chelse, have distinct alse on the shaft (Topsent's dents laterales), but these are nar- row and their lateral edges are parallel. 4. Sigmata; they reach a more considerable size than is commonly the case, and in this respect they are exceedingly varying; they are of the common sigma- form, sometimes a little irregular, and their form may be somewhat varying, they may also be plane or contorted to some extent, mostly only to a slight degree. The length varies from o-ic) mm down to o-o45 mm , and the thickness varies in proportion from o-on mm to ooo2 mm . Monstrous forms of sigmata may occur, and especially one form is not rarely seen, in which one end is split into two or more points, as figured by Fristedt I.e. fig. 39. Besides sigmata are found quite singly some bodies which I must suppose to be developmental forms of sigmata; they are curved like the axis of a sigma, and the ends are tapering, but they are quite, or to a higher or smaller degree, wanting the recurved ends. They have been measured of lengths from 0-058 — o-i8' nm with thicknesses from o - ooi— o-oo25 m,n . Thus this sigma seems to reach a considerable thickness, before its ends are properly developed. Embryos. In some of the specimens embryos were found scattered in the body of the sponge, sometimes singly, sometimes several ones together. They were roundish, of a diameter of about i mm . Their spiculation shows some peculiarities. Of megasclera they have very fine styli, generally with PORIFKRA. II. 13 a somewhat swollen upper end; they were measured to a length of 0-25 — o^o 1 "" 1 and a thickness at the upper end of ca. o-oo2 ram . Of microsclera they have only the middle form of chelse, which occur in all stages of development, as also fully developed, but they are considerably smaller than in the fully developed sponge, only reaching a length of oo3 mmI )- Quite the same observation has been made by Ridlev and Deudv with regard to the embryos of Esperella mammtformis, where the aniso- chelse of the embryos had a length of o-e>5 mra , while in the grown sponge their length was o-c>7 mm . In the opinion of these authors this fact, however, has no especial peculiarity, as, according to their view of the growth of the chela, the small chelae may quite simply grow to their full size. The specimens with embryos were taken during the month of July. Locality: Station 28, 65 14' Lat. N., 55 42' Long W., depth 420 fathoms; station 73, 62 58' Lat. N., 23° 28' Long. W., depth 486 fathoms; station 81, 6i° 44' Lat. N., 27 00' Long. W., depth 485 fathoms; station 127, 66° 33' Lat. N., 20° 05' Long. W., depth 44 fathoms. It has further been taken on 65 39' Lat. N., 28 25' Long. W., depth 553 fathoms (the East-Greenland expedition 1891 — 92). Altogether five or six specimens. The mentioned localities are situated to the north and south of Iceland, in the Denmark Strait and in the Davis Strait. Geogr. distr. Between Scotland and the Faroe Islands, depth 440 fathoms ('Porcupine , Carter); the eastern coast of Greenland, depth 140 fathoms (Fristedt); at the Azores, depth 1196 fathoms (Top- sent). Carter's Unknown sponge is, no doubt, identical with E.villosa, it was taken by the Porcu- pine ■>, between Scotland and the Faroe Islands, 59 56' Lat. N., 6° 27' Long. W., depth 363 fathoms; but it is to be noted that the bottom temperature was here — 0-3°, while on all the other localities of the species it has been positive. 2. E. Normani Bow. PI. VIII, Fig. 2 a— d. 1866. Isodictya Normani Bowerbank, Mon. Brit. Spong. II, 320, 31, III, 141, PI. LVI, figs. 1 — 5. 1880. Ampkilectus Normani Vosmaer, Notes from the Leyden Museum, II, 117, 25. 1885. Esperia Normani Fristedt, Kgl. Sv. Akad. Hand., 21, No. 6, 42. 1893. Esperella Normani Levinsen, Det vidensk. Udbytte af Kanonbaaden Hauch s Togter, 422, 19, Tab. I, figs. 37—49. Incrusting or more or less massive or cushion-shaped (sometimes somewhat branched). The dermal membrane thin, without spicules, resting on the skeleton below; it is pierced by the ends of the fibres, and the surface therefore is finely shaggy. Oscula scattered, most frequently on the end of slightly marked, conical projections. The skeleton of a re.nierid structure with polyspicular primary fibres and most frequently single transverse spicules. Spicula : megasclera curved styli o-/6~u-jj""" ; microsclera of one form, isochelce palmatce 0-020 — o m o2i""". The typical form of this species is incrusting, especially on Hydroidea and branched Bryozoa; it may be of varying thickness and consequently somewhat varying in form ; most frequently it forms larger or smaller covers, or it becomes cushion-shaped or lumpy. It seems, however, also to be ') As all spicules are of the same size, or, at all events, of about the same size in small and large specimens of one species, it is to be supposed that verv soon after the sponge having fixed itself, chelae are formed of the size normal to the species. z . PORIFERA. II. able partlv to assume a free, branched form, as stated by Levin sen I.e. The specimen of Levin sen, however, has incrusted a Hydroid, and presumably its form is partly owing to this fact; but the speci- men has also free branches, in which nothing of the Hydroid seems to be found, as also the primary fibres of the branches may be found running longitudinally, while, if the question was of a cover, thev would have to be supposed to run from the middle, from the body incrusted, perpendicularly on the surface. The largest specimen in hand has a greatest extent of ca. 75 mrc . The colour (inspirit) is light yellowish. The consistent is rather loose and soft. The dermal membrane is thin and transparent without spicules; it is supported by the skeleton below and pierced by the ends ol the fibres, conse- quently the stir/ace is finely shaggy. On account of the apertures of the incurrent canals shining through, the surface gets the netlike appearance, as is found, for instance, in most Re ///era-species. The fores are very close-set in the dermal membrane, so that it is reduced to a network; they are round and of an average size of 0-05 — cri 1 ""'. Oscula are scattered on the surface; they have generally a diameter of from a little more than one to 3""" ; they are situated on the top of more or less marked, but always low, flatly conical projections. The skeleton is of a renierid structure. It consists of fibres running from the base towards the surface where they pierce the dermal membrane. These fibres are polyspicular, and they have generally, as stated by Bower bank and Levin sen, about three spicules in breadth; sometimes also a little more. The transverse fibres are almost always only represented by single spicules, they form no coherent fibres, and they are situated very irregularly. The distance between the primary fibres is on an average ca. o-i5 mm . In the deeper layers of the sponge the skeleton is irregular, and here no distinction can be made between primary and secondary fibres. Spongiu is found in the skeleton, especially distinctly in the nodes, but it is white and exceedingly clear, and therefore not easily observed. Spicula: a. Megasclera are somewhat curved styli; most frequently the curve is even, only rarely it is a little sharp; it is generally found in the middle, sometimes nearer to the head-end; the opposite end is evenly and rather long tapering. They are somewhat varying in length, partly in one individual, and partly in different individuals; upon the whole the length of the styli in the specimens in hand is between 0-16 and o-25 mm . Also the thickness is varying, and is between ca. 0-0057— o-oii4 mmI ). Such is the thickness of the spicules that seem to be fullgrown, but developmental forms of every thickness down to quite fine ones are also found; they are only very little shorter than the fullgrown ones. b. Microsclera; these are only found of one kind viz. isochelae palmatse; they are a little curved, but the middle part of the shaft, between the alae of the two ends, is straight or sometimes slightly curved inwardly; this middle part is about one third of the length. The tooth is of about the same length as the alee, and its breadth is like that of the alse taken together. On the sides the tooth and the alse bend towards each other, but when the chela is viewed from the side these recurvings, on account of their fineness, are almost not to be distinguished. The length of the chelse is 0-020— 0-021 mm , and their breadth is ca. 0-0057"™. Of tne chelae developmental forms are found; the youngest one observed appears as a thin staff -with rather long recurvings in both ends, without ') In some specimens the needles have an average length of 0-23— 0-25""" with an average thickness of o-oimm; in others the length is on an average 0-17 — o-2o'» m with a thickness of o-oo7 mm . PORIFERA. II. 15 or almost without any beginning of the ake or of the plate of the tooth. The developmental forms have the same length or about the same length as the fullgrown ones. The chela; are found through- out the sponge, and in no small number in the dermal membrane. Locality: The Faroe Islands, 9 miles to the east of the Nolso revolving light, depth ca. 30 fathoms; 6 miles north and to west of Kalso, depth 60 fathoms (Tli. Mortensen); the Westmann Islands (Saemundsen). Six specimens or fragments in all. Grogr. distr. The species is hitherto known to the south as far as the Channel, Guernsey (Bowerbank), Luc and Le Portel (Topsent); farther north it has been taken off Bohuslan (Fristedt), and in the Cattegat on depths from 6 l! , to 10 fathoms (Levinseu). 3. E. sp. (?Alderi Bow.) PI. VIII, Fig. 3 a— c. We have a quite small specimen of an Espcriopsis-species sitting on a worm-tube, which specimen has a skeletal structure similar to that of the preceding species. The primary fibres have a few more spicules alongside each other, and they also pierce the dermal membrane, so that the sur- face is shaggy; but the spicules are different. Megasclera are styli, most frequently rather strongly curved and with an evenly tapering, rather long point. Their length is between 0-38 and o-44 mm , and the thickness is about o-oi mm . Microsclera are isochelse palmatae of a similar structure as in the pre- ceding species, but they are straight or almost straight; besides they are a little larger, their length being 0-025 — o-028 mm and the breadth ca. ooy" 1 '". Also of these chelae developmental forms were found of the same appearance as in the preceding species. The chelae of this species show a peculiarity, which, however, is not found in all of them, and which may be more or less marked where it is found. It consists in the fact that the recurved final part of the axis, which must be supposed to run along the middle of the tooth, some way down the tooth bends off from it inward, and, when the chela is viewed from the side, appears as a projecting point or knob on the inside of it ; when the chela is viewed from the front it appears through the tooth as a little tubercle close to the edge. As mentioned, the feature, hovewer, is far from being a constant one, in some of the chelae it is not found, and it may also be found singly in other species. — Lambe (Proceed, and Transact, of the Roy. Soc. Canada, X, 1893, Sec. IV, p. 68 seq.) has described four Espcriopsis- species, which, to judge from the figures (no mention is made of it in the text), have chelae, in which the mentioned structure is strongly marked. As is well known, the same structure is again found in the chelae of the genus Homoeodictya, and this genus or subgenus has been established just on this structure. The Esperiopsis-species showing this structure of the chela-, to be sure, are closely allied, but as the character does not seem to be a constant one, it can here scarcely be used as a generic mark. Locality: St. 127, 66° 33' Lat. N., 20 05' Long. W.; depth 44 fathoms. Geogr. distr. E. Alderi Bow. is from Northumberland. Note. The Esperiopsis-species placed by Bowerbank under the genus Isodictya, appear to be closely allied, and there is a great probability that Bowerbank has established too many species, but it will not be possible, without a close examination of the type specimens, to unravel the species; j6 porifera. ii. Vosmaer refers E.Alderi as a synonym to Normani, and also Topsent has made considerable re- ductions, and has for instance referred Alderi to fucorum, but for the present nothing can be said of the correctness of these identifications. When I have thought that the present species might possibly be Alderi, the only reason has been the size of the spicules; the peculiarity of the structure of the chela: would scarcely have been observed by Bowerbank. 4. E. pedicellata n. sp. PI. I, Fig. 2. PL VIII, Fig. 4a-c. Erect, stalked , somewhat club-shaped ; the upper part lobate or winged. The surface slightly shaggy ; the dermal membrane thin. The skeleton an irregular network of polysplenia)- longitudinal fibres and irregularly scattered spicules. Spicula : J/egasclera styli 5 mm ; the thickness of the shaft is ca. ooo4 mm . Most frequently these chela; are a little twisted, so that the two teeth are not quite in one plane. Of this chela I have seen a few developmental forms, but only rather grown ones with half-developed tooth and alae. 3. Sigmata; these are more or less contort; they reach to a rather considerable size, but are very varying in this respect, the length being between o-03 ,nm and o-o85 ,nm , and the thickness proportionally 0-002— o-oo6'" m . These sigmata show an interesting fact well worth to be noticed. Towards the bendings the shaft generally shows a slight expansion (as seen in Pl.VIII, fig. 5 g); this is not owing to the shaft here being thicker, but to the fact that it is somewhat compressed. When a sigma is seen under the microscope, the hook that on account of the twisting is turned towards the beholder (in the figure the upper one), appears also narrower than the other, and the compression may also be seen on broken sigmata where a transverse section is seen; the transverse section seems to be somewhat triangular with the narrowest edge turned inward. Of these sigmata developmental forms of different thickness are not rarely found; the finer they are, the less developed are the recurved ends; in the very finest ones, of a thickness of scarcely o-ooi mm , the recurved ends are not yet formed. The mentioned structure of the end parts of the shaft may already be traced in the developmental forms. 4. Forcipes; these are of the common, more or less hairpin-like, form with a round curve above and two more or less parallel legs; the legs are most frequently slightly diverging, but may also be quite parallel, or slightly converging, the latter, however, being perhaps only apparentlv the fact and owing to a twisting. They are thorny, which is, however, on account of their smallness, only very little conspicuous; the legs end in a quite small knob-like swelling. When the forcipes are seen under sufficiently great magnifying powers the thorns are seen to be found especially on the inner side of the legs; they are comparatively long, and directed a little upward; also on the upper side of the curve some smaller thorns are found, and there seems likewise most frequently or always to be found a small thorn on the inner side of each knob. A slight granulation may also in most cases be seen 011 the other parts of the forceps. Sometimes the legs are not of equal length. These forcipes are exceedingly small and may easily be overlooked. Their length is o-oiy™" 1 , the thickness at the curve, where it is greatest, is ca. o-ooi mm ; quite few, somewhat larger forcipes were seen. The microsclera are found as well throughout the tissue as in the dermal membrane; in the tissue sigmata are of most frequent occurrence, while in the dermal membrane the two forms of chela.' seem to be found most frequently. Locality: The Davis Strait, depth 80—100 fathoms (Th. Holm), a couple of fragments. Remarks: This species has a quite interesting spiculatiou, and it is the first Esficr/opsis-species, in which forcipes have been found. Therefore there might be some doubt with regard to its being referred to this genus, and there might be a possibility of referring it to Forcepia Cart. As, however, the species has no special dermal spicules, and thus wants a character very significant to the Myxillru\ 20 POR1FERA. II. and as foreipes also occur outside of the genus Forcepia, and the occurrence of these bodies therefore scarcely alone is sufficient for the establishing of a genus, I think it most natural to refer the present species to the genus Esperiopsis. Topsent (Resultats des Campagn. scient du Prince de Monaco, Fasc. II, 1892, 100, PI. VI, fig- 5, PI. X, fig. 9) has established a species Forcepia versatilis wanting dermal spicules; but in embryos found in the sponge small diactinal spicules were found which Topsent takes to represent the dermal spicules, but they are not further developed, so that the species later on has none of them. This species, however, is no Foreefia, but an Asbestopluma, as will be more particularly mentioned under this genus. 6. E. flagellum n. sp. PI. IX, Fig. 1 a— h. Jncrusting; the surface slightly uneven from projecting bundles of spicules ; the dermal mem- brane thin without spicules. The skeleton irregular consisting of polyspicular fibres and bundles of spicules. No spongin. Spic?ila: Megasclera styli o-jp — 0-44"""; microsclera of four forms, isochelce pa Una to 1 of two forms, large ones 0-04 j — o-o8j""". small ones 0-018 — 0-021""": common sigmata o-oq$— 0-2 $"""; flagel- late sigmata o~oj — owj. This species grows as a quite thin incrustation on a dead branch of Ampheiia oculata otherwise very much overgrown by Bryozoa. On the branch are further found an fophon, a Mycale placoides, and a Hamacantha Bowerbankii. With regard to the outer form of the species can only be said that it is a quite thin crust; its contour is irregular, following the form of the substratum, and the limits are otherwise most frequently only seen with much difficulty. Its greatest extent may be given to about 40""", the thickness is only one or two millimetres. The colour (in spirit) is yellowish or slightly reddish yellow. The consistency is loose. The surface has small and scattered projections owing to projecting bundles of spicules, but by examination with a magnifying-glass they are only very little conspicuous. The dermal membrane is thin, without any particidar skeleton only provided with micro- sclera. Oscula and pores have not been found. The skeleton consists chiefly of short fibres or bundles of spicules rising from the base up through the sponge. Sometimes they meet upwards pyramidally^ and give rise to the unevennesses of the skin. They may also be longer and run almost parallel to the surface finally bending into it; these longer fibres may also be branching. Here and there scattered bundles of spicules and a few- scattered spicules are seen. The fibres are polyspicular, and the average thickness may be given to o - 05 mm . Spongin has not been observed and seems not to be found. Spicula: a. Megasclera are slender, straight styli, generally with a very slightly swollen head end, and thus approaching subtylostyli; they are of about equal thickness in their whole length, and the point is short and bounded by rather straight lines. The length is rather constant, varying from 0-39 — o-44 mm , the thickness is o - oo6 — o-oc>7 mm . Developmental forms of the styli occur singly, down to quite fine ones that are long tapering, b. Microsclera; of these four forms are found, two forms of isochelse palmatse, larger and smaller ones, common sigmata, and flagellate sigmata. 1. The large iso- chelse are straight, the alas stretch so far down the shaft, that the free middle part is less than one third PORIl'KRA. II. 21 of the length, the lateral edges diverge towards the middle of the chela, and are rather much refolded; the tooth is a little narrower than the alee taken together, but of the same or about the same length, and it increases also in breadth towards the end; it is likewise hollow inward. Tnberculnm is longish. When the chela is seen obliquely from behind, the axis may be seen to continue as a thickening down the middle of the tooth and stop a little before the end; this point may often, when the chela is seen from the front, appear as a small tuberculum. The size of this chela varies rather much, the length from 0-043— o-o83 mm , and the breadth proportionally from 0-015— °'° 2 4 mm - 2 - The small is o chelae have a slightly curved shaft, the free middle part of the shaft is less than one third of the length. The tooth is a little narrower than the alte taken together and of about the same length; the alae are much refolded. The length of these chelae is between o-oi8 ram and 0-02 i mm , and the breadth is ca. o-oo4 m,n . 3. Sigmata of the common form; these are curved in the common way, and the ends are highly, almost rectangularly recurved. They are larger than is commonly the case, but vary much in size; the length is between 0-095 and o-25 mm , and their thickness is 0-005— o-oi mm . ° f these sigmata a few developmental forms were found; they are fine and want the recurved ends, they were found of lengths up to the greatest length of the sigma. 4. Flagellate sigmata; these are long sigmata curved in such a way as to get two parallel arms, the ends are pointed and recurved in a hooklike manner almost in a right angle, the recurved parts sometimes reach each other. They are exceedingly varying as to size, the longer axis from 0-03— o-i3 m,n , and the shorter axis from 0-024— oo83 mm , tne thickness in the middle is 0-0018— o-oo5 mm ; otherwise the greatest thickness is not here, but at the ends just before the recurving. These sigmata are plane. Of this form I have seen a single developmental form; it was of the same form as the fullgrown ones, but without the recurved ends. All the forms of microsclera occur both in the dermal membrane and in the other tissue of the sponge; the common sigmata are found in greater numbers than the flagellate ones, and are upon the whole the forms of the microsclera most frequently found. This interesting species is very closely allied to the E. decora described by Topsent (Resultats des Camp, scient. du Prince de Monaco, Fasc. XXV, 212, PI. XVII, fig. 8); this latter species forms also a quite thin incrustation, and the skeletal structure seems to be the same. Also the spiculation is much the same, as well with regard to the megascleres as to the microscleres, and also in the occur- rence of the flagellate sigma, which is formed in quite the same way in both species. But with regard to the spiculation, besides some difference in the size of the spicules, the differences are found, that the chelae in decora seem to be of three forms, and that trichodragmata are found in this species. This latter fact especially forms a distinct character, whereas the two largest forms of chelae in decora are all but equal. Remarks: The occurrence in this species of the form of sigmata that I have called flagellate sigmata, is very interesting and surprising; this form has hitherto only been known in the two Grllius- species flagellifer and porosus, and in the Porziella clavismpta from the Azores established by Topsent in 1896 (Bull, de la Soc. de France, XXI, 147, fig. a— d), which the author in 1904 in the work quoted above (223, PI. XVI, fig. 5, PI. XVIII, fig. 7) refers to Hamacantha. The sigma occurring in the present species is of a quite similar form as those of the mentioned two GW/zky-species, the only difference being that in the latter one arm is generally longer than the other, while in the present species both 22 PORIFERA. II. arms are of equal length, in which feature this sigma quite agrees with those of as well E. decora as H. claviscepta. It is also of some importance that the developmental form of this sigma has been found here, as it has not been known before. Localitx: Ingolf, station 55, 63" 33' Lat. N., 15- 02' Long. W., depth 316 fathoms. Only one specimen. 7. E. typichela n. sp. PI. I, Fig. 3. PI. IX, Fig. 2 a— c, Figs. 3—4. Incrusting, the surface with very small, close-set , conical projections, (end with scattered long, flagelliform appendices ; the dermal membrane thin, without spicules. The skeleton consists of polysplenia/ fibres, chiefly running from the base to the surface. Spongin -van ting. Spicula : Megasclera styh o-jj o-yj"""/ microsclera, isochelcr palmatm of two forms, larger ones 0-064 — o-ojtf"'". smaller ones 0-021 — 0-025""". The specimen in hand of this species grows incrustiug on a Hornera lichenoides, but it grows over more branches, so that it forms a continuous plate, and it grows quite round the Hornera so as to show a surface on both sides. The greatest extent of the sponge is 30 mn \ and the thickness from surface to surface reaches at most 5""". The consistency is soft. The colour (in spirit) is gray. The surface is to the naked eye smooth, but under a magnifying glass it is seen to be covered with close- set, conical projections owing to the ends of the fibres. Further it shows the peculiarity that long, fine, flagelliform appendices formed by a spicula-fibre project scattered round on the sponge. In the present state of the sponge these free fibres are lying along the surface and appear to the naked eye as sinuous threads. The dermal membrane is exceedingly thin; it contains no skeleton, and rests on the mentioned projecting ends of the fibres. Pores are found in the dermal membrane in the areas between the projecting ends of the fibres; they are generally so close-set, that the membrane becomes a network. They are round to oval, and their size was measured to 0-059 — o-i4 mm . Oscitla were not found. The skeleton. It is a difficult task to examine the structure of the skeleton continuously on account of the soft consistency of the sponge. It consists chiefly of polyspicular fibres running from the base to the surface where they project and form the conical projections mentioned above. The average thickness of the fibres is ca. o-03 mm . No transverse fibres are formed between these fibres, but fibres or bundles of spicules are found, especially down towards the base, placed horizontally or irregularly. The mentioned fibres that run from the base to the surface, are only short on account of the small thickness of the sponge; but frequently they are not placed perpendicularly, but more or less obliquely, and often they are very decumbent, and so become considerably longer. The projections caused by the fibres, therefore, are not perpendicular to the surface, but more or less oblique. Now a few of the projecting fibres are prolonged and form the mentioned long, fine appendices scattered on the surface of the sponge. These appendices, which thus seem simply to be prolonged fibres, are at the base a little thicker than the other projections having here a thickness of ca. o-i6 mm , but they taper towards the point. They may reach a length of up to io mm . They consist of a fibre surrounded by a thin layer of tissue. At the base of the fibre there are many spicules alongside, but towards the PORIFKRA. II. 23 point they grow fewer, and at the very end they are quite few, in quite undamaged appendices per- haps only a single one. In the covering layer of tissue an abundance of microsclera is found; along the fibre, at least to the middle of it, the large chela is arranged in beautiful rosettes, and between these rosettes the little chela is found in dense crowdings (PI. IX, fig. 4), but forming no rosettes. The sponge is throughout highly intervowen with sand and small silicious particles. Spicula: a. Megasclera are very slender, straight styli; they taper evenly, but not much, towards the pointed end, the point itself is rather short. The length varies from c/33— o-45 mn ', and the thick- ness from 0-004 — o-oo57 mm . Finer developmental forms are found, but only singly, b. Microsclera are two forms of isochelse palmatse. 1. The large chelse are of a very regular and beautiful form. The shaft is straight, the free middle part a little curved inward. The alse reach so far down the shaft, that the free middle part is only about one fourth of the length, and their sides are somewhat refolded. The tooth is of the same length as the alse and only a little narrower. Its edge is curved a little inward. Tuberculum is longish, broadest below. When the tooth is seen from the inside the axis may be seen some way down it. Not rarely a slight twisting of the chela is observed. The length is 0-064 — 0-075™"', anc * the breadth is o-o2i m,n . A few developmental forms of this chela were seen. 2. The small chela has a quite slightly curved shaft, the end parts are so long, that the free middle part of the shaft is quite short. The lateral edges of the alas form a far more curved line than in the large chela, and their lower edge is straight. The sides of the alte are somewhat refolded. The tooth is of the same breadth as the alas, and the tuberculum is a little longish. The alse and the tooth form a very small angle with each other. The length is 0-021 — o-o25 mm , quite singly specimens were seen of a length of 0035""". The breadth is o-oo8 mm . The occurrence of the chelse is quite singular; to be sure they are to be found throughout the tissue, but especially at the surface. The large chela occurs as rosettes which seem to be attached to the fibres, especially at the dermal membrane, but not in this membrane itself. It is seen arranged in rosettes in the layer of tissue on the projecting ends of the fibres. Also the small chelse are especially seen at the surface; they do not form rosettes but occur in groups or dense crowdings. Both kinds of chelae occur also, as before mentioned, in the flagelliform appendices. The occurrence of the large chela in typical rosettes is rather interesting, as this fact is otherwise not known in the isochelse, but has only been observed in anisochelse. Carter meutions rosettes of chelae in Mycale titubans, and thinks here to have found isochelse in rosettes; as will be mentioned hereafter, under the species in question, its chelae, however, are anisochelse. This species shows itself to be related to the preceding one; the megasclera are of the same form, and also the large chela is of the same structure. Also the skeletal structure seems to be the same as well with regard to the arrangement as to the fact that spongin is wanting. On the other hand the small chela is of a different structure, and no kind of sigmata is found. Locality: Forsblads fjord, East Greenland, depth 50—90 fathoms (the Amdrup-Expedition 1900). Only one specimen. Mycale Gray. The habitus may pass through the whole series of forms from thinner or thicker incrustations through massive forms to erect , often lobate, or finally branched or more or less irregularly leaf- or cup-shaped 24 PORIFERA. II. /onus that will then be more or less symmetrical. The skeleton consists of polysplenia)- fibres; in the erect forms it is well developed, often dendritically branched, in the massive and incrusting forms it may be of renierid or more irregular structure, or if may in the incrusting ones consist of slightly branched fibres running from the base to the surface without transverse fibres. Spot/gin is most frequently found, in varying, frequently only slight amount. Spicula : Megasclera monactinal, styli or subtylostyli; microsclera; the characteristic microsclera are anisochehv palmatec of one or more than one form, the largest ones often in rosettes: to these may be added sigmata, trichodragmata, toxa. and. rarely, small isochehe palmafte. The genus Mycalc, like Esperiopsis, passes through a series of forms from thin incrustations to erect, rather symmetrical forms. The development of the skeleton is connected with this fact. The lowest skeletal structure I take to be the one occurring in some thin, incrusting forms, and consisting of fibres running from the base to the surface and sometimes slightly branching, as has been described and figured by Vosmaer and Pekelharing with regard to M. aegagropila (Verhandl. d. Koninkl. Akad, v. Wetensch. te Amsterdam, 1898, 2, VI, No. 3, PI. I, fig. 3—4). The fibres are here quite free without connecting transverse fibres or transverse spicules. This structure quite without transverse fibres is, perhaps, owing to the fact that these sponges are quite thin crusts. When we get to thicker or massive species, transverse fibres or transverse spicides are found, and the skeleton gets a renierid or more irregular structure which in the erect forms mav pass to a dendritic structure. The typical il/ycvz/r-auisochela, as it is found for instance in lingua and placoidcs, is a very characteristic one distinguished by reaching a rather considerable size. It may vary very much in size without showing distinctly marked, different sizes, but it may also occur in several well-marked sizes or forms; the largest ones very often occur in rosettes, which is not known to be the case with regard to the smaller ones. Small isochelse may occur, but rarely, for instance in M. parishii Bow., where they occur together with anisochelse, sigmata, and trichodragmata, and in M. phtmosa Cart., where, according to Carter, they occur together with anisochelae, sigmata, and toxa. Also sigmata may be found of more than one size, for instance in M. macrosigma Liudgren. — The microsclera mentioned in the diagnosis may occur in different combinations. In some species only anisochelae are found, either of one or more than one form, further chelae and sigmata, chelae, sigmata, and tricho- dragmata, which latter combination is very frequent, then chelae, sigmata, and toxa, or chelae and trichodragmata; finally, as mentioned, small isochelse may in a few instances be added to the combination. 1. M. placoides Cart. PI. IX, Fig. 5 a-1. 1876. Esperia placoides Carter, Ann. Mag. Nat. Hist. Ser. 4, XVIII, 316, PI. XIII, fig. 12, PL XV, fig. 32. 1880. Vosmaer, Notes from the Leyden Museum, II, 147, 32. 1892. Esperella placoides Topseut, Resultats des Campagn. scient. du Prince de Monaco, Fasc. II, 89, PI. I, fig. 15. Erect, somexuhat club-shaped, sometimes compressed or more irregular. Tin dermal membrane thin, without spicules, pierced by projecting spicules, and the surface consequently finely shaggy ; it is provided with sinuous or branched fore-furrows. Oscula in flic upper part of the sponge on the top of PORIFERA. II. 25 small oscular cones. The skeleton consists of polyspicular fibres branching up through the sponge. The spicules piercing the dermal membrane are smaller than the other spicules of the skeleton. Spicula: Megasclera styli or subtylos/yli. sometimes with the upper end formed like a handle; the styli of the skeleton o-jjy—o-ji 5""". those of the dermal membrane o-j — 0-5"""; microsclera of three forms, anisochela palmetto- 0-025 — 0-092""". the large ones frequently in rosettes ; sigmata 0-0/7 — 0-027"""; rhaphides in trichodragmata 0-043 — 0-085""". Mycale placoides has been rather carefully described by Carter in the place quoted, and he has rendered an account of most of the characteristic structural features. On account of the great resemblance between this species and the following one, it will, however, be of importance that a full description is given of both of them. The form of the sponge seems to be somewhat varying, but is always erect; the hitherto known specimens, mentioned and figured by Carter and Top sent, are erect and more or less cylindrical or club-shaped, being somewhat narrowed below. All the specimens before me are more or less damaged, but with regard to the form it may, however, be decided from them that the sponge, besides the mentioned form of which I have some specimens, may also be more or less compressed, or be drawn out into some broad and irregular lobes reaching through the whole length. The specimens mentioned by Carter and Top sent had a height of 6-5 — 9 c,n . Most of the specimens before me are considerably larger, the club-shaped specimens thus up to a height of 17"". The largest specimen consists of some fragments which were stated by the collector, Dr. Morten sen, to have belonged to one specimen. Its form has been somewhat compressed, presumably as a thick leaf. It has been a very large specimen; but the lower part wanting, and, I suppose, to a rather great extent, the height cannot be given, but the breadth above has been ca. 30 cm , and the thickness 5—6™. The consistency is soft and not elastic, and therefore the sponge, in spite of the thick fibres, is rather fragile. The mentioned largest specimen is stated to have been very slimy, when it was taken up in the trawl. The colour (in spirit) is generally whitish yellow. The surface, as is well known, has a characteristic appearance being completely furrowed by a large number of sinuous or branching fur- rows that may be arranged in very different ways. The parts between the furrows are finely shaggy from projecting spicules, while the furrows are smooth. The dermal membrane is thin without any particular skeleton; it is supported by the ends of the fibres, the spicules of which are spread in a penicillate way, and project a little through it, and it is stretched over the furrows of the surface. Pores and oscula. As has been very well described by Carter, the mentioned furrows in the surface are pore areas. They may show a very different arrangement, being sinuous and branched in many different ways. They may be placed rather near to, or more far from, each other, and conse- quently the parts between them may be larger or smaller plates, or may be reduced to projecting knobs or rather long keels. Then the furrows may be quite narrow, almost quite closed, or broad and flat; this latter feature is probably mostly caused by the greater or lesser contraction of the skin in the place in question. The pores are found in the membrane that is stretched in the furrow, most frequently very close-set, so that the membrane resembles a sieve. Of the strings of tissue separating the pores, some are generally thicker principal strings, between which the pores are placed more or less arranged in series. These strings, which may be distinctly seen by means of a magnifying glass, pass The Ingolf-Expedition VI. 2. 4 2 6 PORIFERA. II. iii the more narrow areas more or less transversely from one side of the furrow to the other. The size of the pores is generally 0-035 — o-i mm . The thin pore membrane is not directly supported by the skeleton, and only microsclera are found in it, especially chelae, partly in beautiful rosettes, partly scattered, but also sigmata and rhaphides, singly and as trichodragmata. As mentioned by Ridley and Dendy under Esperella murrayi (1. c. 67), a fine longitudinal striation is also found here in the strings of tissue between the pores, which, as supposed by the mentioned authors, is perhaps owing to muscle-like fibres. Frequently no pores are seen in the membrane of the furrows, but then it is to be supposed that they are closed. Oscula are found in the upper end of the sponge, and sometimes some way clown the sides; they are formed like small cones, of a height of only a few millimetres. The oscular aperture is found at their point, and has a diameter of 1 — 2 mm . The wall of the oscular cone has a dense spiculation of needles placed parallel to the longitudinal axis of the cone; these needles are of the same form as those supporting the dermal membrane, that is to say of the smaller form. On the upper part of the sponge, where oscula are especially found, the pore furrows are wanting or are only found to a slight degree. The skeleton is of the dendritic type; from the base fibres issue which anastomose and branch, most frequently more or less irregularly, up through the sponge. The real, single fibres are generally not particularly thick, at most about o-47 mm ; but especially in the lower part of the sponge several fibres are often united into strings apparently forming a single fibre, and reaching to a considerable thickness, but under the microscope they are seen to be formed of several close-set fibres. Towards the surface the fibres branch copiously, and run as parallel fibres of a thickness of about o-o6 mm and with a distance of 0-25 — o^o" 1 ™ towards the dermal membrane; here the spicules spread in a peni- cillate way and pierce the membrane. Where the pore furrows are found, the fibres pass off to the sides, so that the membrane in the furrow is not supported or pierced by spicules. No transverse fibres are found, but between the fibres and their finer branchings spicules and bundles of spicules are scattered irregularly and more or less densely. In the outer part of the skeleton, at the surface, it becomes more regular by the fact that the ends of the fibres here run parallelly with fixed inter- vals; some transversely placed spicules are here found interwoven between the fibres. These transverse spicules, as well here as deeper in the sponge, are generally of a form differing somewhat from that of the spicules forming the fibres; they belong to the shorter and thicker forms, and are always a little curved. The spicules in the outer eud of the fibres, which are spread in a penicillate way, con- sist of styli of a definite kind, smaller than the other styli of the skeleton, as has already been observed by Carter. Spongin is found in the fibres uniting the spicules; but nevertheless the fibres are loose and little capable of resistance; with regard to this fact, however, there is some difference between different individuals. Spicula: a. Megasclera are styli or slightly marked subtylostyli. They are of two forms, as the spicules that support the dermal membrane spread in a penicillate way, as mentioned, are smaller and of a form somewhat different from that of the skeletal spicules. These spicules supporting the dermal membrane may, for the sake of shortness, be called dermal spicules, although they cannot be said to form any particular dermal skeleton. The skeletal styli are straight, or have a larger or smaller curve nearest to the upper end; this end is rounded and sometimes slightly swollen. The PORIFERA. II. upper end of the styli are not rarely formed as stated by Bowerbank with regard to M. constricta and M. lingua; in this case a kind of handle is found on the spicule, the upper end being narrowed for a shorter or longer way and then passing rather abruptly into the thicker part. This structure of the spicule may be more or less marked, and is frequently almost imperceptible, and it is very often quite wanting. The feature may, moreover, be different in different individuals, so that it is found more frequently and more marked in one individual than in another. The needle is thickest in the middle, and the tapering end runs into a point rather much varying in length as well in one indivi- dual as in different individuals. The length of the styli varies from 0-447 — o7i5 mm and the thickness from o-oio — o - oi6 mm ; these are the limits within which I have found the needle varying in the species, but there may be some difference in different individuals, and in one individual the needles do not generally show so great a variation. The limits most frequently found may be given as to length 0-5 — o - 65 mm , as to thickness croii— 001 $ mm . As before mentioned, the transverse spicules occurring out- side of the fibres are oftenest a little shorter and thicker than those forming the fibres, and they are curved. Finer developmental forms are only seen in small numbers. The dermal spicules are straight; they are of a particular form, their thickest part being found nearest to the pointed end, while they are evenly tapering towards the rounded end, which is often very slightly expanded. Sometimes at the rounded end they may be of the same handle-like form, as is mentioned in the skeletal spicules. While their size and the length of their point, and by these features to some degree also their form, is rather constant in one individual, they vary not a little in different individuals. It is, however, chiefly only the length of the point which is varying, but this fact again influences the form and the length of the whole spicule. In some individuals the point is quite short or even rounded, and then the thicker part of the spicule is found close to the point; in others the point is even and of a middle length, and in others again very long, up to quite exceedingly long and thin; in the latter the thicker part of the spicule is then found about in the middle. That it is really only the point that is of varying length, is also seen by the fact that the longer the point, the longer is the spicule. The length varies altogether in the different individuals from 03 — o'5 mm ; in the separate individuals it is, for instance, 0-3— o^S" 1 ™, 0-35 — 042™'", 042— o - 5 mm , and these lengths are quite corresponding to the smaller or greater length of the point. The thickness, which is also a little varying, as well in the species as in the separate individual, is O'OC^— o-oi mm . b. Microsclcra are auisochelse palmatse, sigmata, and rhaphides in trichodragmata. 1. The anisochelse are of the common Mycale-type; the shaft is slightly curved, the alse of the larger end are broad and diverge towards the middle of the chela, and their sides are much refolded. The tooth is rather narrow, and most frequently somewhat rounded at the end; the tuberculum is long and narrow, and there is a rather broad falx. The alse of the smaller end are broad, and diverge only a little towards the middle of the chela, and their sides are much refolded; the tooth is rather broad, and the end is straightly cut off, the tuberculum is small and elliptic. Both alse and tooth here being broad they leave only a narrow slit between them. While the alse and the tooth of the larger end converge towards the end of the chela, this is only to a slight degree the case with those of the smaller end, and consequently this end gets a peculiar, straightly cut off appearance. Both the alse and the tooth in the smaller end of the chela are curved about in a circular line, so that a transverse section through the chela would here be almost a circle. These 28 PORIFERA. II. chelae vary very much in size. Their greatest length is 0-092""", but there may be a little difference in different individuals, so that in some they reach at most o - o86 mm . The thickness of the shaft is ca. 0'005— o-ooy" 1 " 1 , and the greatest breadth is ca. 0030 — 0'035 mra . This largest form of the chelae may vary a little in form in different individuals, especially the upper end may be a little shorter or longer. From the greatest length the chelae may now vary down to so small a size as 0-025"""; at the same time the dimensions of the several parts of the chela are also altered, the ends, especially the larger one, becoming longer in proportion to the free middle part of the shaft. While thus in the large chelae the larger end, the free middle part, and the smaller end are in a mutual proportion about as 2:2:1. these parts are in the smallest chelae about as 2:1:1. In the series of variations of the chelae the forms which would follow nearest to the largest ones, are of very rare occurrence, so that the chelae would almost seem to fall in two groups, the larger ones only little varying in size, and the smaller ones very varying in size. That such is the fact would also be implied by another thing, viz. that only the large chelae occur in rosettes, while the small ones are never seen arranged in that manner. This recalls to some degree the feature in several Dcswacd/a-species, in which only the larger of the two occurring forms of sigmata are developed in bundles, while the smaller form is never arranged in that way. Developmental forms of the chelae are also found, but most frequently only in very small numbers; only in a few individuals they were a little more numerous. As the chelae they are found in all lengths. The youngest developmental form I have seen, is an exceedingly fine staff recurved in both ends, a little more in one end than in the other. During their growth as well the shaft as the recurved parts grow thicker while in the curves the axis remain thin; the alae and the plate of the tooth is by and by developed, by which fact the parts of the axis situated in them disappears or is effaced, while the free middle part of the axis gets its final thickness. The part of the axis situated in the curve itself, on the other hand, is not thickened, but keeps its original thickness, and from this part inward is developed the thin plate, the socalled falx, connecting tooth and shaft. The falx is already developed at an early stage. The chelae are found both throughout the sponge and in the dermal membrane, as well singly as in rosettes; as above mentioned only the large ones are found in rosettes; these rosettes are seen especially often in the pore membrane covering the furrows. The large chelae are also found singly. 2. Sigmata; these are of the common form, and are almost always more or less contort. Their length, which may be somewhat dependent 011 the degree of contortion, is between 0-017— 0-027"™; r ' ie thickness is between ca. 00008— oooi4 m, °. 3. Rhaphides; these are sometimes seen singly, but most frequently in bundles, trichodragmata; the length of the individual rhaphides varies from 0-043 — o , o85 ,nm ; such is the variation in the species, but in the single individuals it is not so great, for instance 0-047— o-o67'" m an d 0064 — 0-085""". In individuals with the shortest styli also the shortest rhaphides are found. The thickness is about o-ooi mm . The thickness of the bundles is 0-013 — o-oi8 ,nm . Sigmata and rhaphides occur both in the dermal membrane and throughout the sponge, especially rhaphides in dragmata are of frequent occurrence in all parts of the tissue. Locality: Station 1, 62 30' Lat. N., 8° 21' Long. W., depth 132 fathoms; station 7, 63 13' Lat. N., 15 41' Long. W., depth 600 fathoms; station 55, 63 33' Lat. N., 15 02' Long. W., depth 316 fathoms. Further it has been taken on 65 39' Lat N., 28 25' Long. W., depth 553 fathoms (the East-Greenland Expedition 1891—92); 64 15' Lat. N., n° 15' Long. W., depth 192 fathoms (Wandel); the bay of Skage- PORIFERA. II. 29 strand in Iceland (Wandel); at the north end of Nolso, depth ca. 100 fathoms (Th. Mortensen); 62 30' L,atN., 1 ° 56' Long. E., depth 275 fathoms (Ad. Jensen, the cruise of the « Michael Sars» 1902); altogether ca. nine more or less damaged specimens. The localities are situated in the Denmark Strait, off the northern coast of Iceland, between Iceland and the Faroe Islands, off the east coast of the Faroe Islands, and to the north east of the Shetland Islands. Geogr. distr. Besides on the localities mentioned above the species has been taken about 40 miles to the north north west of the Shetland Islands, depth 345 fathoms (the Porcupines, Carter); further it has been taken farther south, off New Foundland, depth 673 fathoms (Topsent). 2. M. lingua Bow. PI. IX, Fig. 6 a— f. 1866. Hymeniacidon lingua Bowerbank, Mon. of Brit. Sponges, II, 187, 24. 1866. Desmacidon const-rictus Bowerbank, ibid., II, 350, 4. 1874. Raphiodesma lingua Bowerbank. ibid., Ill, 119, PL XLVII, fig. 8, 237, PI. LXXVII, figs. 1—6. 1874. Desmacidon constrictiis Bowerbank, ibid., Ill, 181, PI. LXXI, figs. 3 — 10. 1880. Esprria lingua Vosmaer, Notes from the Leyden Museum, II, 146, 24. 1886. Esperclla Vosmaeri Levinsen, Dijmphna-Togtets zool.-bot. Udbytte, 20, 15, Tab. XXX, Fig. 11 — 14. 1887. Esperia lingua Fristedt, Vega-Exp. vetensk. Iakttag. IV, 449. 1892. Esperclla lingua Topsent, Resultats des Campagn. scient. du Prince de Monaco, Fasc. II, 88. 1896. Lambe, Transact, of the Roy. Soc. of Canada, ser. 2, II, sect. IV, 186, PL I, figs. 6, 6 a — f. 1904. Esperclla lingua Topsent, 1. c, Fasc. XXV, 200. Erect and somewhat tongue-shaped, or more irregular. The dermal membrane thin, supported by projecting spicules, the surface consequently finely shaggy ; it is provided with sinuous or branched pore-furrows. Oscula in the zipper half op the sponge, on the top of small oscular cones. The skeleton consists of 'polysplenia? fibres branching up through the sponge The spicules piercing the dermal membrane op the same size as the other spicules of the skeleton. Spicula: Megasclera styli or slightly marked subtylostyli, sometimes with the upper end formed like a handle, o-jj — r/j"""; microsclera of three forms, auisochehe palmata 0-028 — 0-002""", the larger ones often in rosettes; sigmata 0-021 — o-oj2"""; rhaphides in fricho- dragmata 0-042 — o-oyS""". This species presents many points of resemblance with the preceding one. It is erect, and those of the specimens in hand that are tolerably well preserved, are of a longish, somewhat com- pressed form, and may, in correspondence with the name, very well be designated as tongue-shaped. The largest specimen, which is much lengthened, is of a length of 23 cm , but of a breadth of only 5'5 cm , and the thickness is scarcely 3 cm . Another specimen is of a height of io cm , and the smallest specimen, which is more roundish, but also compressed, is of a height of a little more than 2 cm . The consistency is rather soft, and the sponge is easily torn. The colour (in spirit) is most frequently whitish yellow or gray. The surface resembles that of the preceding species, and furrows of the same kind arranged in different ways are found. These furrows are also here smooth, while the other parts are a little , PORIFERA. II. more shaggv than in the preceding species. The dermal membrane is thin and has no particular skeleton, but is supported by the ends of the fibres projecting through it, and by the transverse spicules connecting the fibres. Pores and oscula. As mentioned above we find in this sponge as in the preceding one furrows in the surface that may present a very varying arrangement. These fur- rows are also here pore areas, the dermal membrane being stretched over them and provided with pores quite as in the preceding species. The pores are placed very close, and most frequently more or less arranged in transverse series separated by thicker principal strings. Also here a fine, muscle-like longitudinal striation is found in the strings of the tissue between the pores, which striation was seen still more distinctly than in the preceding species. The pores are round or oval, and in the examined pore area they had an average diameter of about 0-015— o-o2 m,n . The pore furrows in the specimens in hand are smaller and are present in smaller numbers than in the preceding species; in one of the specimens they are all quite closed, and then they appear as quite narrow keels arranged in a somewhat netlike manner. Pores seem also to be found outside the pore furrows; but it is diffi- cult to decide this fact by material which is not fresh or especially well preserved. Ridley and Dendy state it to be found in E. murrayi. Oscula are small, more or less steep cones of a height of 2 — 3 ,nm . The oscular aperture is found in the end of these cones. The wall of the cones is provided with a very dense speculation of spicules parallel to the longitudinal axis of the cone, and their ends project round the aperture. In the larger specimens oscula are found in rather large numbers and are- restricted to the upper half of the sponge. The skeleton is of a dendritic type, and is constructed as in the preceding species. It consists of fibres branching from the base up through the sponge and anastomosing. Also here the single fibres are closely united into thicker ones that are apparently single ones, and these thicker fibres are often not cylindrical. The single fibres have been measured to a thickness of at most o-65 mm . Towards the surface the skeleton sends forth finer branches running parallelly, and supporting and piercing the dermal membrane; between these fibres some transverse spicules are found. The ends of the fibres which appear as bundles of spicules, are in this species formed of spicules of the same kind as the other spicules of the fibres, so that no specially formed dermal spicules are found. The transverse spi- cules found between the fibres that are parallel and run towards the surface, are also in this species of a form somewhat different from the form of those forming the fibres, being shorter, thicker, and curved. A slight amount of spongiu unites the spicules of the fibres, but is only little conspicuous. Spiatla: The spiculation of this species is upon the whole like that of the preceding one. a. Mcgasclera are styli, or may have a slight tendency towards subtylostyli. Most of them are straight, but some are slightly curved ; they are fusiform, tapering towards both ends, which holds good especi- ally with regard to the shorter and thicker ones. The upper end is rounded and sometimes quite slightly swollen ; the handle-like form of this end mentioned under the preceding species, is also some- times found in the present one, and also here developed to very different degrees. The other end of the needles runs into a point, which may, especially in different individuals, be very varying in length, from being quite rounded to a long, fine point. The length of the needles is rather varying, as well in one individual as in different individuals. As mentioned the transverse spicules between the fibres running towards the surface are shorter and thicker than the other spicules, a distinct limit, however, PORIFERA. II. 31 cannot be drawn; these spicules do not vary much in length in the different individuals, and the smallest length of the needles, therefore, is rather constant. The greatest length of the needles, on the other hand, varies much in different individuals, and this length is dependent on the length of the point, so that the longer and finer the point is, the longer is the needle. The boundaries of the length of the styli upon the whole in the species are 0-53 — ri5 mm , but when given for separate indivi- duals, the length of the point being also taken into consideration, we get for instance 0-56— o-So^"" 1 the point more or less rounded; cr6o— o'95 mm the point short; 0-65— i' m " the point rather long; 0-65 — ri5™ the point very long. The thickness of the needles is somewhat varying, and the longest ones are far from being the thickest ones, the mentioned transverse spicules being both the shortest and the thickest; the thickness is between ca. o-oi3 mm and cro2 mm . Some difference may be found in diffe- rent individuals, especially with regard to the greatest thickness, which sometimes does not exceed o-oi8" ,m . Finer developmental forms are seen, but only singly, b. Microsclcra: these are anisochelse palmatse, sigmata, and rhaphides in trichodragmata. 1. The anisochelse are of the common Mycale- type and constructed in almost quite the same way as the chela; of the preceding species, the only difference being that the tooth of the upper end is broader. The greatest length of the chelae is o-oo,2 mm , but there may be some difference in different individuals. The thickness of the shaft is ca. o-oo8 mm , and the greatest breadth is 0-028— cro4 n,m . From the greatest length the chelae vary in size down to o-028 mra , and at the same time the proportionate dimensions of the different parts are altered in a similar way as in the preceding species. The chelae are not rarely a little twisted. Also in the present species a break is found between the large chelae and the largest of the smaller ones, and also here only the large chelae are found in rosettes. A few developmental forms were found quite corre- sponding to those in placoidcs. 2. Sigmata of the common form, often somewhat irregular and more or less contort; their length, which is much dependent on the curve, is between 0-021 and o-032 mm , and the thickness varies from o-ooio— oooi5 mm . 3. Trichodragmata; the single rhaphides are of a length of 0-042— o-078 mm , most frequently about midway between the two sizes; the thickness is 00008— o-ooi4 mm . The rhaphides are almost only seen in trichodragmata, of a thickness of o-on— . 0I ^mm Th e microselera are numerous throughout the sponge, sigmata are of especially frequent occurrence in the dermal membrane. The large chelae occur in many places, in rosettes in enormous numbers. Remarks: In the above mentioned largest specimen taken at Upernivik, there are found here and there in the sponge, but in very small numbers, some peculiar spicules that may be designated as tylostrongyla, and whose form may be seen in the annexed figure (fig. 1), which represents three of these spicules and the end of a fourth, and shows different forms of the end-swelling. One end is rounded, while the other is swollen to a more or less pyriform expansion. These spicules always occur in a particular way being only found in the projecting bundles of spicules, always only one or a few spicules in the same bundle, and only here and there, so that many of the projecting bundles may be examined without any being found. In the bundle they are always placed with the swollen end outward, so that it is seen between the points of the other projecting spicules. It is easily seen that these spicules, with the exception of the swelling, are in all other respects of quite the same 32 PORIFERA. II. form as the normal spicules of the species; the not-swollen end is rounded or quite slightly dilated, in other words it has quite the same form as in the normal spicules, and consequently it is the point of the spicule that is transformed. Also its position agrees with this view, it having, like the other projecting spicules, the head-end turned inward. This spicule, which occurs here so scattered and in small numbers, must be regarded as an abnormal form, and in the bundles transitional forms are also found with slightly swollen or only rounded outer end. That the spicule should be of extraneous origin is quite out of the question, as well on account of its form, as its always occurring in the same way. - It would seem that projecting dermal spicules upon the whole are somewhat liable to be influenced with regard to the form, especially of the outer end, of which among others Mycale placoidcs furnishes an instance bv its dermal spicules that vary so characteristically in different indi- viduals. The occurrence of this spicule, however, is not without interest, as it is of a quite similar form and occurrence as the dermal spicules in Rhaphidotheca MarsJiall-Hallii Saville-Kent (Ann. Mag. Nat. Hist. 4. Ser. VI, 219, PI. XV, figs. 1 — 7) from the coast of Spain, and Rhaphidotheca afjinis Carter (Journ. of the Roy. Micr. Soc. II, 497, PI. XVII, figs. 1 and 3) from a locality between Scot- land and the Faroe Islands, which latter species is probably identical with the former '). This species has the common Mycale-spicxilation quite as in lingua, but in all, or almost all, the spicules of the pro- jecting bundles the outer end is swollen in a pear-shaped manner. (Saville-Kent says expressly that a few pointed spicules are found in the bundles.) In this species the feature has thus no doubt become normal for all or almost all projecting spicules. The opinions advanced by Carter (Ann. Mag. Nat. Hist. 5, I, 170, Journ. of the Roy. Micr. Soc. 1. c, and Ann. Mag. Nat. Hist. 5, IX, 299) that these spicules should be foreign and embodied by the sponge, and that their form should have been altered by the sponge after the em- bodiment, with reference to which latter fact he, in the place last quoted, even says: « has been shown to be adventitious or appropriated, having first belonged to another sponge», are devoid of all foundation, and it is a peculiar thing that Carter has not been able to see, from their form and way of occurrence, that they belonged to the sponge. The whole question debated in the places quoted, whether needles may occur turning the pointed end inward in the sponge and projecting with the head-end, is likewise of no consequence, as it is a fact that the mentioned spicules turn their head-end inward in the sponge. Fig. 1. X165. ■) Vosmaer (Notes from the Leyden Museum, II, 141, 8) refers, with a query, Rhaphidotheca Marshall-Hallii, as a sy- nonym to Espcrella nodosa O. S. In the description of Schmidt, however, there is no base at all for this referring. PORIFERA. II. 33 - Saville Kent's species, however, is not the only one with such spicules, and the transformation of the ends of the projecting needles seems in some instances to go still farther. Tops en t (Bull, de la Soc. de Fr. XXI, 1896, 149, fig. 2 a— f) has thus established a new genus, Gomphostegia ') with the species loricata that is also a Mycaliue with the typical A/yfTrt/e-spiculation, but with projecting spicules the outer ends of which are widened to a slightly crenelated disc and thus form a mail. In these needles, which Topsent calls Exotyles», the head-end, which is turned inward in the sponge, is formed in quite the same way as in the other styli in the sponge. Thus there seems to be a gradual development in the formation of the ends of the projecting dermal spicules from forms where it only occurs as an abnormal fact, through such where it has become a normal feature, to forms in which it has been developed to an exceedingly high degree. Locality: Station 3, 63° 35' Lat. N., 70 24' Long. W., depth 272 fathoms ; station 54, 63° 08' Lat. N., 1 5 40' Long. W., depth 691 fathoms; further it has been taken at Upernivik (the Reverend Mr. Soren- sen); 72 53' Lat. N., 20 36' Long. W., depth 96 fathoms (the East-Greenland Expedition 1891 — 92); 63 15' Lat. N., 9 35' Long. W., depth 270 fathoms (Wandel); 62 30' Lat. N., i° 56' Long. E., depth 275 fathoms (Ad. Jensen, the cruise of the < Michael Sars -, 1902). Altogether six specimens, most of which damaged. The localities are situated in the Davis Strait, off East-Greenland, between Iceland and the Faroe Islands, and to the north east of the Shetland Islands. Geogr. distr. The species has further been taken off the southern Greenland, 6i° 15' Lat. N., 49 11' Long. W., depth 70 fathoms, and 59 33' Lat. N., 43 25' Long. W., depth 120 fathoms (Fristedt); the northern coast of Scotland and the Shetland Islands (Bowerbank); the Kara Sea, depth 65 fathoms (Levinsen); the eastern coast of Canada, depths 75 and 80 fathoms (Lambe); off the north-west coast of Spain, depths 71, 133, and 160 fathoms, off New Foundland, depths 673 and 82 fathoms, and at the Azores, depths 69 and 185 fathoms (Topsent). Thus the species is in the mentioned seas distributed about from 73 to 40 Lat. N., with a bathymetrical distribution from 65 — 691 fathoms. Remarks on the species Mycale placoides and lingua. These two species are exceedingly closely related to each other. The external form, the pore furrows, the structure of the skeleton, and, partly, the spiculation show great conformity. Among the distinguishing characters the most important one is the presence of particular dermal spicules (the spicules that are spread in a peuicillate way and carry the dermal membrane) in placoides, while in lingua these spicules are of the same form and size as the other spicules of the skeleton. It is especially this character that is of value as a sure distinctive mark between the two species. Further the tooth in the larger end of the chela is broader in lingua than in placoides, as is seen from PI. XI, fig. 5 e compared with fig. 6 c. Then the styli are upon the whole longer and thicker in lingua than in placoides, and finally the sigmata are also most frequently larger in lingua than in placoides. If I have determined the two species as placoides and lingua, I must remark that Carter J ) In the work by Topsent from 1904 (p. 202, PI. XIV, fig. 15) quoted in the list of synonyms he has acknowledged that Gomphostegia is synonymous with Rhaphidothcca. The Ingolf Expedition. VI. 2. 5 ~. PORIFERA. II. expressly says of placoides that the spicules projecting through the dermal membrane are smaller than the others, while his other description agrees very well with the specimens before me. I have then determined the other species as lingua, but from the description of Bowerbank it is not to be seen with certainty, whether he has possibly had placoides or perhaps both species before him. Topsent, 1. c. 1892, enumerates both lingua and placoidcs, but gives no description, so that it cannot be seen, which characters he takes to be the distinguishing ones. The peculiar handle-like formation of the upper end of the styli cannot be used, as this formation, as is seen from the preceding descriptions, is found in both species, and may occur very varying with regard to its frequency and degree of marking. Therefore I also follow Topsent in regarding Bowerbank's lingua and const ricta as one species. When Topsent in the place quoted mentions that he has seen specimens of lingua with pore furrows, and others without such and with a uniform, slightly shaggy surface, I must suppose that in the latter the pore furrows have been closed, the slight keels then found being often only very little conspicuous. I have omitted to quote Esperia constricta Vosmaer (Niederl. Arch, fur Zool. Suppl. Band I, 1881—82, 45), and Esperia lingua Vosmaer (Bejdr. tot de Dierk. i2 te Afl. 3 die Gedeelte, 1885, 30), as it is impossible to decide, which of the two species mentioned here the author has had before him. The figures in the former place, PI. Ill, fig. 99, and in the latter place, PI. V, fig. 73, might both look like dermal spicules of M. placoides, but nothing can be decided with certainty. Neither have I quoted Esperia constricta Marenzeller (Die oesterreich. Polarst. Jan Mayen, III, 10), the author's good and rather copious account of the variation of the spicules would seem to indicate that he has had both species before him. Thus with regard to the geographical distribution we can, from these facts, only infer that one or the other, or both species occur in the Barent Sea between 72 and 75° Lat. N., and between 15 and 36 Long. E., on depths between 128 and 175 fathoms, as well as at Jan Mayen on depths from ca. 48—200 fathoms. The E. Vosmaer i established by Levinsen 1. c. I have, by an examination of the type specimen, found to be identical with M. lingua; Levinsen does not mention rhaphides, which, however, are present. The E. murrayi established by Ridley and Dendy Challeng. Report, XX, 67, PI. XIII, figs, n, 13, 14, 16, 17, 18; PI. XIV, figs. 1, 1 a) is by Topsent 1. c. referred to E. placoides, and by Lambe 1. c. to E. lingua. If the chela figured by Ridley and Dendy fig. 17 is correct with regard to the tooth of its smaller end, a specific identity with placoides or lingua is out of the question, neither does the description of the dermal skeleton or the length o-053 mm given for sigmata agree with any of the two species. The E. lingua var. arctica established by Fri- stedt (Vega Exp. vetensk. Iakttag. IV, 449, PI. 25, figs. 20—24, PI. 29, fig. 18) cannot be E. lingua, only on account of the measures given for the spicules, but must be another, independent species. 3. M. ovulum O. Schmidt. PI. I, Figs. 6—8, PI. X, Fig. 1 a— e. 1870. Chalinula ovulum O.Schmidt, Grundzuge einer Spongienfauna des atlant. Gebiet, 38, Taf.V, Fig. 1 '). 1873. °- Schmidt, Jahresber. d. Coram, zur wissensch. Unters. deutsch. Meere in Kiel fiir 1871, 99. ') In the explanation of the plate the name, presumably by a misprint, is Chalinula ovum. PORIFERA. II. 35 1875. Espcria lanugo O. Schmidt, ibid, fiir 1872 — 73, 118. 1879. Espcria stohnifera Merejkowsky, Mem. de l'Acad. imp. des sc. de St. Petersb., Ser. 7, XXVI, Nr. 7, 22, PL I, figs. 13, 14, PI. Ill, figs. 4, 5, 12—19 and 23—29. 1891. Chalinula ovulum Grentzenberg, Spongienfauna der Ostsee, Inaug. Dissert, Kiel 1891, 27, Fig. 13, 14. 1891. Esperclla lanugo Grentzenberg, ibid. 34, Fig. 22 — 26. 1893. Esperella ovulum Levinsen, Det vidensk. Udbytte af Kanonbaaden Hauchs Togter, 423, 20, Tab. I, Fig. 40—41. 1903. Esperclla lanugo Arnesen, Bergens Mns. Aarb. 1903, Nr. 1, 10, Taf. I, Fig. 6. 1903. Mycale lanugo Thiele, Arch, fiir Naturgesch. 1903, 381, Taf. XXI, Fig. n. Egg-shaped, or the larger specimens lengthened or quite irregular. The dermal membrane thin pierced by the projecting spicula-bundles, and the surface therefore finely shaggy. In the regular, egg- shaped specimens one single osculum, in the irregular ones several scattered oscula. The skeleton a rather regular network of polyspicular, primary fibres and singly placed transverse spicules. Spicula: Megasclera rather short, curved styli 0-166 — o-j/""": microsclera of one form , anisochelec palmatm 0-020 — 0-045""", characteristic by their smaller end being comparatively large. This species grows almost always on Algce, on Hydroids, or on erect Bryozoa. The specimens in hand are thus growing on Ptilota pectinata and on Odontlialia dentata; of Hydroids it is found on Diphasia abietina, HydraUmania falcata, Gra miliaria abietina, Scrtularella sp., and Halecium ' sp., and of Brvozoa on Micropora borealis. The smaller specimens are formed as regular round or egg-shaped, oftenest flat cushions, and grow most frequently more or less unilaterally on the Alga or the Hydroid; when a little larger they generally grow round it, but often keep a rather regular, somewhat flattened egg-shaped form. In this condition, in which the sponge has a rather characteristic appearance, its longitudinal extent is from 4 to 12 — i5 mm . When it grows larger it loses the regular form; thus it frequently in- creases in length, and becomes longish incrustations 011 the branches of the Algae and Hydroids; it may also grow more roundly and become large lumps spreading over several branches. This form, I sup- pose, is most frequently formed by a coalescing of more individuals; such a coalescing, at all events, is frequently seen and gives rise to irregular forms. The largest specimen in hand of this form is of a greatest extent of 55' nm . The colour (in spirit) is lightly or more darkly yellow. The consistency is swampv and slightly elastic. The surface is very finely shaggy from projecting bundles of spicules. The dermal membrane is thin, has no skeleton of its own, but is supported by the projecting bundles of spicules. The pores are found in the membrane, often close-set and in large numbers; most frequently their form is oval, and they have been measured to sizes from 0-012 — o-i5' nm . Oscula. In specimens of the regular, egg-shaped form only one osculum is found situated on one side; it is circular and of a diameter of 1 — i*5 mm , its edge is most frequently slightly projecting. In the larger, irregular specimens several oscula are found; sometimes each of them is placed on a slight projection, and this, perhaps, is a mark of the original individuals that are coalesced into one specimen. The skeleton is of a quite regular structure consisting of polyspicular fibres. From the inmost part of the sponge, that is to say from the part attached to the incrusted foreign body, which body, in the sponges that are growing round it, runs through the middle of the sponge, fibres pass towards the surface. 36 PORIFERA. II. Xearest to the foreign body the skeleton is least regular, but a little farther out regular fibres occur running parallel to each other, continuing to the surface, and piercing the dermal membrane. These fibres are polyspicular with rather many spicules alongside, most frequently six to eight; with regard to this fact, however, some difference may occur in different individuals, so that the fibres may contain both fewer and more spicules. The distance between the fibres is about cri2 mm , and the average thick- ness of the fibres may be given as o-035 mm . Coherent transverse fibres are not formed, but between the primary fibres transverse spicules are found, most frequently singly, and without any regularity. Some- times a tendency towards a more regular net of meshes may appear towards the surface. In many of the individuals the primary fibres do not pass straight towards the surface, but show a tendency to turn upward towards the upturned end of the sponge, so that the fibres in the egg-shaped roundgrowing speci- mens may radiate to all sides, but at the same time turn upward, so that it may be seen, especially in a longitudinal section, which end of the sponge has been turned up, and which has been turned down- wards. Spongin is found in the fibres, but only to a small amount, and it is exeedingly white and clear. Sptcnla: a. Mcgasclera are styli; they are more or less, often rather much, curved, and the curve is almost always nearest to the upper end. The other end passes evenly into a point of middle length, the outer end of which is most frequently somewhat shorter pointed. The needles are thickest about the middle, also tapering somewhat towards the rounded end, and being thus a little fusiform. The length is between o-i66 mm and o-3i ram , but in many individuals the ueedles do not vary so much; thus individuals are found in which they reach no greater length than cr23 ram . Also the thickness is somewhat varying, from croo6— o-n mm , and also in this respect some difference is found in different in- dividuals. The thickest spicules are not always the longest ones. Besides the fully developed forms developmental forms of every degree of thickness occur, and in some individuals these forms are found in large numbers scattered in the tissue outside of the skeleton formed by the fibres; they were found down to an exceeding fineness, less than o-ooi mm , and developmental forms of this thickness were measured to a length of 0-15"™. The developmental forms, in contradistinction to the fully developed ones, are long pointed. The individuals copiously provided with developmental forms of the styli seemed upon the whole to be in a state of lively formation of spicules, developmental forms of the chelae being also seen abundantly, b. Microsclera are only of one kind, anisochelsepalmatse. They are characteristic by the smaller end being comparatively large, larger than is common in the Mycale- anisochelae. Their shaft is straight, and they are otherwise of the common type; the alee of both ends are highly folded round on the side; the tooth of the larger end is narrower than the alse and rounded at the end; the tooth of the smaller end is of the same breadth as the alse, and it is some- what pointed, which seems to be owing to the fact that the axis continues quite to the point of the tooth; the alse of this end pass to the shaft in such a way as to make their upper or free edge parallel to the upper edge of the tooth. In each end an oblong tuberculum is found. The chelse vary not a little in size and also in form; thus they may be more broad or more narrow, and the comparative sizes of the ends may be somewhat different; in a few cases there is almost no difference between the two ends, so that the chelse approaches an isochela in form; generally, however, they are not to be confounded with isochelse, as it is most frequently only the teeth that are of equal or about equal size, while the alse of one end continue to be smaller than those of the other, as shown in PORIFERA. II. 37 fig. i d, PI. X. The smaller the chela, the smaller is the free middle part of the shaft in proportion to the ends, which are, accordingly, comparatively longer than in the larger chelae. The length of the chelse varies between 0020 — o-045 mm , the breadth between 0-007 — o-oi5 mm , and the thickness of the shaft between o - ooi — o - oo2 mm . In several of the individuals developmental forms are found abundantly, corre- sponding to all sizes of the chelae; the youngest forms are so fine as to be observed only with diffi- culty, of a thickness of ca. o - ooo5' nm . These fine forms consist only of the axis, which is already of full length. From these voungest forms and to the fully developed chela all transitional forms are found. Of the cheke the small ones are present in by far the largest number, while the large ones are more scarce, and do not appear to be found in all individuals, some being found, in which the greatest observed length of the chela is ca. 0'028 mm . The chelse are found throughout the sponge; the largest may occur in rosettes, but this fact has only been observed in very few cases; also Merejkowsky mentions rosettes. Remarks: When Schmidt, in 1870, established this species he referred it to the genus Cl/a- linula, overlooking the chelae, and in 1875 he made the same mistake. Also Grentzenberg 1. c. must have failed to see the chelse, there being no reason to doubt that it has really been the present species he has had before him. hevinsen was the first who, in 1893, when examining the type specimen of Schmidt, which is found in our museum, discovered the chelse, and referred the species to the proper genus. In 1875 Schmidt 1. c. established a species Mycalc (Esperia) lanugo; the de- scription, as is generally the case, is exceedingly brief, and no figures are given. It is, however, said of the chelse that they are distinguished by the smaller end being larger than is else the case in Espcrclla, and that in a few chelse both ends are equal, and just this fact is a very characteristic mark of M. ovulum. The terms used of the exterior, correspond also very well, it being said that it is roundish «von weicher, flockiger Beschaffeuheit» , which latter character Schmidt has even expressed in the name. Now it is a fact that specimens of ovulum sometimes, especially when of a whitish colour, may have a peculiar, woolly appearance, about like a little lump of wadding. In 1891 Grentzenberg 1. c. enumerates E. lanugo, and gives figures of it, and to judge both from the habitus figure and the rather bad figure of the chela, as well as from the whole description, there can be no doubt that the species is identical with ovulum 1 ). This, again, corroborates the referring of Schmidt's lanugo to ovulum; for, as far as can be seen, Grentzenberg has of this species only had the material of Schmidt. Thus we find the peculiarity that as well Schmidt as Grentzenberg has, both of them and each in a work of his own, enumerated one species as two different ones, partly as Chalinula ovulum, partly as Esperclla lanugo; this peculiarity, however, may so far be understood, as the reason is that in one case the chelse have been overlooked. Under E. lanugo Grentzenberg mentions that besides the common skeleton it possesses ein aus Fasern gebildetes Geriist, dass Schmidt nicht erwahnt . He describes further that in a transverse section is seen about in the middle of the sponge a circular fibre, inside of which run four or five radiate ones coalescing in the middle. He figures this structure in fig. 24. The author thinks these fibres to be spongin fibres, and he mentions some cells which are said to form those fibres in a '; I have later had the opportunity of examining a type specimen of M. lanugo, which proved the species to be identical with ovulum. 38 PORIFERA. II. peculiar way. Now it is not said whether spicules are found in these fibres, but they are figured without such. A spongin skeleton of a so peculiar kind, not seen to be in any way connected with the other skeleton, would be quite unique. By a look at fig. 24 it is obvious that the question cannot be of spongin fibres; through the middle of each of the radiate fibres runs a line which is said to mark the coalescing, but in reality shows that the figured things are evidently vegetable cells. As before mentioned the sponge frequently grows round Algte, which is also the case with the figure of the exterior given by Grentzenberg, and then the Alga runs about through the middle of the sponge; the author also says that the peculiar circular fibre is found nearly in the middle of the sponge. To be sure there can be no doubt that by the cutting out of the transverse section of the sponge the incrusted Alga — it looks like a Polysiphonia -- has been cut through, and it is this transverse section which has been interpreted as the peculiar circular fibre with the radiate fibres inside. The Espcria stolonifcra established by Merejkowsky 1. c. is by Levinsen referred to ovuhim as a synonym, and to judge from the description and figures they are surely identical. I have, however, in no case observed the net of thin off-shoots mentioned by Merejkowsky for some of his specimens. Locality: Of this species we have a great number of specimens, all from Greenland, Iceland, and the Faroe Islands. Greenland, without any designation of locality (Schmidt's type specimen) ; Egedes- miude (M. Porsild); the Ingolf, off Bredebugt, on station 87, depth no fathoms; Rostin in Bredebugt (H. Jonsson); Onundarfjord, depth 10 fathoms (the author); to the east of Bakkefjord, depth ca. 70 fathoms (Hallas); Skulavig in Seydisfjord, depths 6 fathoms and 30 fathoms; Berufjord, depth 10 fathoms (A. C. Johansen); the Faroe Islands (Miiller); at the north point of Nolso, depth ca. 100 fathoms, 6 miles N. to W. of Kalso, depth 60 fathoms, Saudsbugt (Th. Mortensen). Geogr. distr. Besides on the above localities the species has been taken in the Cattegat between Samso and Sealand (L-evinsen 1. a); in Great Belt, depth 24 fathoms, and in the Baltic at Kiel, depth 3—6 fathoms, Darserort, depth 15V2 fathoms, Stoller bank, depth 3—5 fathoms (Schmidt, 1873), further at Bergen and Espevser (Arnesen), finally in the White Sea (Merejkowsky). Note. Three of the My calf -species mentioned in the literature, are with rather great pro- bability to be referred to the present species; I do not, however, venture to decide this question with certainty, or to make any change of names on that account. The first of these species is M. (Isodictya) lobata Bow. (M011. Brit. Spong. II, 326, III, 148, PI. LVIII, figs. 19—22); Bowerbank, to be sure, men- tions «bihamates , which are not figured; but these needles might very well be developmental forms of the cheke, and such a fact might also be implied by the observation that they are «exter-umbonates . The second species is M. (Isodictya) Clarkci Bow. (1. c. II, 330, III, 142, PI. LVI, figs. 11— 15); the figure of the exterior of this species, which grows on Hydroids, is quite similar to longish specimens of M. ovu- lum. Topsent, in his list (Rev. biol. du Nord de la Fr. VII, 15 and 20) has taken this species to be an Espcriopsis, and has referred it as a synonym to E./uconini Johnst. Bowerbank, however, calls the chela « inequi-an eh orate , and the figure also shows an anisochela, but, to be sure, an anisochela in which there is onlv little difference between the two ends, such as occur in M. ovulum. The third species is the E. modesta established by Lambe (Transact, of Roy. Soc. of Canada XII, 1894, Sect. 4, PORIFERA. II. 39 118, PI. Ill, figs, i, i a— d; ibid. Ser. 2, II, 1896, Sect. 4, 188, figs. 7, 7a— d) 1 ); Lambe mentions two kinds of styli, rather thick ones with short point, and thinner ones with long evenly tapering point, but the latter I take to be developmental forms, these having always a longer point than the fully developed ones. 4. M. thaumatochela n. sp. PI. X, Fig. 2 a— g. 1897. Esperella intermedia Vanhoffen (non Schmidt), Gronland Exp. der Gesellsch. fiir Erdkunde zu Berlin, II, 1, 248. Incrusting, The surface shaggy from projecting bundles of spicules ; the dermal membrane thin. The skeleton a tolerably regular network of polyspicular fibres. Spicula: Megasclera styli 0-35— o- 48'"'"; microsclera of two forms, anisochelce palmata- 0-047—0-06'""', anisochelce of a very peculiar structure 0-012— o-o //""". Of this sponge we have only one small specimen growing on a fragment of a shell of Pccten islandicus, and a small, inconsiderable, loose fragment. As to the exterior the sponge is very insigni- ficant, and all the interest attaches to the spicnlation. The specimen is formed as a very thin incru- station, and its greatest extent is i5 mm ; but it looks, however, as if the whole specimen is not found on the fragment of the shell. The thickness is at most i mm . The colour (in spirit) is light grayish-brown The surface is shaggy from projecting bundles of spicules. There is a thin dermal membrane, without spicules as far as I am able to see. In the dermal membrane circular openings are found, of a dia- meter of 0-047 — °'35 mm °f which I take the greater ones to be oscula, and the smaller ones pores. The skeleton consists of polyspicular fibres; as far as I have been able to examine the material, it is formed of fibres running from the base to the surface and projecting through the dermal mem- brane, and of other fibres perpendicular upon the former ones; it seems to be rather regular. In the nodes a slight amount of spongin is seen. Spicula: a. Megasclera are styli, evenly and most frequently slightly, sometimes a little irregularly curved. They have an even point of middle length, which is often somewhat shorter pointed at the outer end. The size of the styli is rather constant, the length is between 0-35 and o^S 01 ™, and the thickness is 0007—0-0115""". b. Microsclera. These are of two kinds, anisochelse palmatae, and some small, peculiarly shaped bodies which may also be characterized as anisochelse. 1. The palmate anisochelse are of a fine regular form and chiefly of the common type. The alse of the larger end, which are much refolded on the side, diverge downward with their lateral edges, and then they curve somewhat upward with a round bend going in to the shaft; the tooth is somewhat narrower than the alse, elliptical, but broadest below and rounded, sometimes with a small pointing. The tooth and alse of the lower end are of about equal breadth ; in the middle of the distal edge of the tooth is generally found a pointing owing to the axis continuing quite to the end, and on either side of the pointing is found a little notch, so that the tooth is tridentate. In each end there is a longish tuberculum. The size of these chelse is rather constant; the length varies from 0-047— o-o6 mm being most frequently about ') Lambe, in both places, writes sp. nov., and has no reference in the latter place; but as the descriptions are almost equal, I suppose it to be his opinion that the species is the same. Otherwise Schmidt has already in 1862 (Spong. adriat Meer) established an E. modesta, so that the name of Lambe's species, at all events, must be changed. 4 PORIKERA. II. o-057 mm , the greatest breadth is 0-020 — 0-022™'", and the thickness of the shaft is o-oo2 mm . These chela- are frequently found in rosettes. Quite single chelae of smaller size are found, down to 0'03 mm . 2. The other silicious body found in the sponge is of a peculiar shape, and on account of its smallness and intricate structure it is difficult to get a clear view of it. Its form may be reduced to the aniso- chelate type. Below it consists apparently of a jar- or slipper-like part and above of four alse issuing from the upper end, which alse on four sides extend down over the slipper-like part. The lower part looks somewhat differently, according as the bod)- is seen from one or the other side, and by a preli- minary examination only two of the four alse are seen, one on either side. By a more thorough examination under sufficiently high magnifying powers it is seen that, when the chela is in a certain position, an axis runs along one side, below turning upward to about the middle of the chela; when the chela is placed in such a way as to turn the axis behind, i. e. away from the beholder, the form of the lower part is all but slipper-like; the exact form of this part is only to be seen with difficulty, but it appears to consist, as usual, of lateral alse issuing from the axis, and of a broad tooth before. Both the alse and the tooth are on the sides folded towards each other, the interstice between them I have not been able to see with certainty, but it is about as shown on PI. X, fig. 2 c. On either side the axis of the chela is in its upper part provided with rather narrow alse separating from the axis about in the middle, and continuing downwards as a single pointed elliptical tooth. Further a free, pointed elliptical ala is found on either side with the flat sides turned laterally, and in the front is found a tooth of the same form. These structures are placed at equal distances from each other, and form the four apparently uniform ake, which pass from above downwards to about three fourths of the length of the chela. The two lateral alse together with the alse of the dorsal side may be regarded as corresponding to the alse of the axis of a common chela. That the lateral alee are not teeth may be seen from the fact that above they are provided with an unsymmetrical, translucent part, while in the tooth there is a symmetrical tuberculum; they are likewise above and behind connected with the ala of the dorsal side. The alse as well as the tooth are best seen when turned to the side so as to be seen from the edge, whereas, when turned towards the beholder, they are only to be seen with much difficult} - , on account of their fineness and transparency. A good view of the mutual position of the parts ma}- be got, when the chela is seen from the end in such a way, that the lower end is turned directly towards the beholder, who will then see an optical transverse section as fig. 2 f, PI. X, where the tooth, the two lateral ake, and the axis are seen at right angles to each other, and in the middle the lower part in connection with the axis and its alse. These chelse are very small, their length varying from 0-012— o-oiy"" 11 , and the breadth being 0-007 — ooo8 mi ". Both the large palmate chelse and the small peculiar ones occur abundantly. This species so peculiar and characteristic by its spiculation has by Vanhoffen 1. c. been determined as E. intermedia O. S. As I have had preparations of the specimens of Vanhoffen, I have been able to decide with certainty thas it is the present species he speaks of. Vanhoffen has, strange to tell, made a mistake with regard to the megascleres, and calls them beiderseits zugespitzte », whereas the are distinct styli. Schmidt says of his Esperia intermedia that it has < unspitzige Nadeln , which I take to be a misprint for , and further his species is provided with two different \ PORIFERA. II. 41 sorts of chelae, so that an identification with this species, is, for many reasons, excluded. Vanhoffen has further overlooked the peculiar small chelae 1 ). Locality: The whole specimen has been taken by the Iugolf-Expedition at Holstensborg at a depth of 30 fathoms, and the loose fragment has been taken off Cape Dalton, East-Greenland, depth 9 — n fathoms (the Amdrup-Expedition 1900). Gcogr. distr. Vanhoffen has the species from West-Greenland, Karajak-Fjord, and mentions that it occurs as incrustations on worm tubes and Bryozoa. 5. M. titubans O. Schmidt. PI. X, Fig. 3 a. — h. 1870. Desmacidon titubans O. Schmidt, Grundzuge einer Spougienf. des atlant. Gebiet 55, Taf. V, Fig. 18 a — c. 1882. Desmacidon titubans Carter, Ann. Mag. Nat. Hist. Ser. 5, IX, 298, PI. XII, fig. 24 a— h. Form? The skeleton an irregular network consisting for the greater part of polyspicular fibres. Spongin wanting. Spicula: Megasclera sty ii of two forms, larger ones o-jp — o-o'""'. smaller o/ics o-j2 — 0-40"""; microsclera of two forms . anisochela of a peculiar, wry form 0-024 — 0-032""", sigmafa o-oj —0-14""". Of this species, so peculiar and characteristic by the form of its chelae, we have only very little material, so that I can only to a slight degree supplement the description given by Schmidt 1. c. as to the exterior and skeletal structure. With regard to the outer form Schmidt only says, unform- licher, unregelmassiger Korper . The fragments in hand are also of a quite irregular form; the largest one is irregularly bifurcate and somewhat flattened; its extent in length is 25™™, but it is probably only a quite ruined fragment The colour (in spirit) is yellow to olive. I can say nothing of its sur- face, pores, or oscula. The skeleton appears as a rather irregular network of mostly polyspicular fibres, and longi- tudinal fibres seem especially to be found, while the other network is quite irregular. Upon the whole the fibres are not strongly marked, and no spongin has been observed. Schmidt says that the small form of styli are found as irregular bundles placed obliquely to the fibres; as far as I have been able to see, however, the fact is not so. The small styli seem to me to occur near the surface and the dermal membrane, and perhaps partly to be lying horizontally in the skin, partly to project as peni- cillate bundles. Spicula: a. Megasclera; these are styli occurring in two different forms, also of different size. The large styli are evenly curved, the curve being almost always found nearest to the head-end and more or less pronounced; the other end tapers to a middle-long, sometimes rather long point. Their length is 0-59 — erg" 11 ", and the thickness is between o-oi5 ram and o-oig" 1 ™. Finer developmental forms are found, but in rather small numbers. The styli of the other form are smaller; they are straight or almost straight, only rarely slightly curved. The head-end is quite slightly swollen, most frequently, l ) On the preparations of Vanhoffen determined as E. intermedia, which he has lent to me, a query is found by the name, and on one of them is added, < ist nicht intermedia , so that Vanhoffen seems himself to have noticed the erroneous determination. The Ingolf-Expedilion. VI. 2. 6 ■ 2 PORIFERA. II. however, to a quite imperceptible degree. The tapering may be somewhat varying, but the point itself is always rather short. The length is 0-32— 0-40"™, and the thickness in the middle is 0-005— o-oo8' n "'. As has been mentioned, these styli, as far as I have been able to decide, occur near the skin. b. M/'cro- sclera are of two forms, chelae and sigmata. 1. The chelae are of a quite peculiar structure, but must be characterized as anisochelae palmatse. They are of a wry form; the shaft is somewhat curved, and besides being bent from behind to before it is also bent a little to the side. The tooth of one end is larger than that of the other, and otherwise the teeth are differently constructed. To facilitate the understanding of the description I call the end with the smaller tooth the upper end. When the chela is placed on the back with the upper end turned upward, and the upper tooth directly towards the beholder, and in such a way, that the upper part of the axis is turned directly upward, then the lower part of the axis is bent a little to the left. The frontside of the upper tooth is then turned directly upward; it reaches to a little more than half the length of the chela, is of a somewhat wry form, and has only a plate-shaped extension to the right; at the upper end a small, triangular tuberculum is found, and there is a small falx. On the upper part of the shaft an ala is only found on the right side; this ala is of a similar form and size as the tooth. When the chela is seen in the mentioned position, tooth and ake are accordingly about opposite to each other. In this position the tooth of the lower end is seen on the left side of the chela, and is seen from the edge, as the front of it is turned out towards the side; it reaches to about the middle of the upper tooth, being therefore most frequently somewhat larger than the latter. If now the chela is turned a fourth part of a turning to the right, so that the upper tooth is seen from the side, the lower tooth will be seen as a warped plate somewhat expanded towards the end, reaching up and bending in towards the shaft; at the base there is a roundish tuberculum. On the left side of the lower part of the shaft an ala is found reaching somewhat farther than the lower end of the ala of the right side, but it is rather narrow and bent forward, and is thus rather inconspicuous. Also on the right side of the lower part a small and short ala is found. When the chela is in the position first mentioned, it is seen, that it is especially the lower part of the shaft which is twisted in such a way, that the lower tooth is turned round on the side. In a few of the fragments in hand the chelae are a little larger than in the others, and in these chelae the plate-shaped end of the lower tooth is often marked off by an incision, and this part is finely dentate in the edge. As men- tioned the chelae van- somewhat in size, and seem especially to be varying in different individuals. The length is between o-024 mm and o-052 mm , when the chelae are regarded collectively, but the variation is not so great in the single individual. In one specimen the length was 0-024 — °'°35 mm > m another 0-034 — o-052'" m . Schmidt has not quite understood the structure of these chelae; especially his figures a and b are quite misleading; figure c, however, showing the chela from the front, is somewhat better. Carter 1. c, on the other hand, has quite misunderstood them, and it might be doubted whether he has had the same species before him, if he did not mention that he has had a preparation of the type specimen of Schmidt. Carter figures and mentions the chela as an isochela, and he figures uniform alae on both sides of the shaft and uniform teeth, the only deviation from the normal form thus being that the chela is somewhat twisted. This, as will have been seen, is a quite wrong representation, and when Carter thinks that this chela with regard to its structure recalls the diancistra in Hamacantha, and PORIFERA. II. 43 consequently will have these referred to the chelae, his theory is of no importance. Carter mentions and figures rosettes; I have also seen such, but the}' were less distinct than elsewhere in Mycale-species. In the rosette the chelae have the end with the larger tooth turned towards the middle of the rosette. 2. Sigmata. They are of a regular sigma-form; the ends are with a round curve bent round to about a right angle. They are plane or slightly contort; especially the smaller forms are contort, while the larger ones are most frequently quite plane. They are very much varying as to size, and may be rather large. The length varies from 0-05 — ci^ 1 ", and the thickness proportionally from crooi8 — o-oo57""". The measures given by Schmidt, are, no doubt, due to an error. As well chelae as sig- mata occur everywhere in very large numbers. In spite of the peculiar chelae of this species, I have placed it under the genus Mycale, because the chelae must be referred to the type anisochelae palmatce, and its skeletal structure being hitherto only imperfectly known, I have thought it most convenient to keep it in this genus. Locality : Station 78, 6o° 37' Lat. N., 27° 52' Dong.W., depth 799 fathoms; station 97, 65° 28' Lat. N., 27° 39' Long. W., depth 450 fathoms. The former station is on the eastern slope of the Reykjanaes-ridge, the latter in the Denmark Strait. Altogether we have only four fragments. Geogr. distr. Florida, depths 174 — 324 fathoms (Schmidt). 6. M. intermedia O. Schmidt. 1874. Espcria intermedia O. Schmidt, Die zweite deutsche Nordpolarfahrt, II, 2, 433, Taf. I, Fig. 40. 1903. Mycale intermedia Thiele, Arch, fur Naturgesch. 1903, 381, Taf. 21, Fig. 12. This species I have not had before me. It would not be possible to recognize it by Schmidt's description, but Thiele has I.e. given a new description of it. Of spicules it has the following forms: a. Megasclera oxea, ca. o4-5 mm long and o-oio— croi2 mm thick; b. Microsclera large anisochelae palmatae in rosettes, 0-05— o-o6 ,nm long, with the smaller end rather large; small anisochelae palmatce ca. croi8 mm ; the latter do not form rosettes. This species deviates from all other Mycale-species by its diactinal megascleres; Thiele there- fore says that there may possibly be some reason for separating it from the genus Mycale, but this he will not do, however, as long as only this one species is known, and in this I follow him. Locality: Northern East-Greenland. Asbestopluma Norman. Erect, stalked forms; t/ic upper part penniform, or with side-branches issuing from all sides of an axis or collected at its upper end, or the sponge formed like a long-stalked cup. The skeleton is exactly corre- sponding to the form, and consists of a- spicula-axis often divided info parallel fibres ; in this axis is in- serted fibres running one through each side-branch. Sometimes a coat with particular, densely interwoven spicules on the stalk. In the skeleton of the axis spongin is found. Spicula ; Megasclera monactinal, slyli or subtylostyli, and, where a coat is found on the stalk, in this coat minutely sptned tylostyli or tylostrongyla ; microsclera: the characteristic microsclera arc small anisochcla' palmata- of a peculiar form, with a strongly marked contrast between the two cuds; to these may be added larger anisochcla' palmata- and sigmata, or only sigmata or forcipes. 6* 44 PORIFERA. II. The generic name Asbestopluma was used for the first time in 1882 by Ray Lankester, who, in a paragraph Dredging in the Norwegian Fjords (Nature XXVI, 478) under the sponges mentions Asbestopluma (a new genus of Norman) . As, however, it was nowhere described, nothing was known of it. In 1901 Top sent, however (Resultats du Voy. du S. Y. Belgica, Spongiaires, 23) has rendered an account of the genus and given a description of it on the basis of a preparation from Norman, and then it turned out that Norman had established the genus Asbestopluma on the species Cladorliiza pennatula of O.Schmidt 1 ). Now Topsent thinks, and, no doubt, justly, that sufficient characters are found to justify the keeping of the genus, which will comprise the symmetrical, Clado- rhiza-Mke forms which are not, as Cladorliiza , provided with ancorae, but with palmate auisochelae. Topsent, however, wants the genus to be interpreted as a sub-genus of Cladorliiza, only separated from it by the mentioned character. I, on the other hand, regard the genus, exactly on account of its chelae, as most closely allied to Mycale, and therefore I place it just after Mycale as an independent genus. It will comprise all the symmetrical forms, hitherto referred to Esperelia, with small anisochelse of the characteristic type more thoroughly mentioned under the different species, either alone or together with other forms of microsclera. Thus the genus is well characterized both with regard to its outer form, its skeletal structure, and its spiculation ; but at the same time it, especially with regard to its outer form and spiculation, divides into three groups that seem to me so strongly marked, that I think it most correct to establish three subgenera for these groups. Asbestopluma Norman s. str. Penniform, lateral branches issuing biserially from an axis, or with la feral branches all round, often, however, showing a distinct bilaterality. The skeleton a spicula-axis divided into parallel fibres or fibre-like farts, in which axis the fibres supporting the lateral branches are inserted. The stalk is coated with a layer containing particular spicules. Spicula: Megasclera styli and subiylostyli, the former in the axial fibres, the latter in the lateral branches, and further irregularly sinuous, minutely spined tylo- styli or tylostrongyla in the coating of the stalk; microsclera: the characteristic anisochelcs palmalce are small, the alee of the larger end pass far down towards the opposite end, which is narrow; further always rigmata and often large anisochelcs palmatte. 1. A. pennatula O. Schmidt. PI. II, Figs. 1— 6. PI. X, Figs. 4a— o, 5—7. 1875. Cladorliiza pennatula O. Schmidt, Jahresber. der Commiss. zur wissensch. Unters. deutsch. Aleere in Kiel fiir 1872 — 73, 1875, 119, Taf. 1, Fig. 14 — 16. 1882. Cladorliiza bihaviatifera Vosmaer, Niederl. Arch, fiir Zoologie, Suppl. Band I, 47, PI. I, figs. 105 — 112. 1885. Espcria bihamatifcra Armauer Hansen, The Norwegian North-Atlantic-Exp. XIII, Spongiadae, partim, 15, PI. Ill, fig. 7, PI. IV, fig. 2, PI. VII, figs. 5 and 14. *) Topsent 1. c. tells that the preparation of Norman had the inscription < Asbestopluma pennatula Schultze , but he thinks, and, no doubt, justly, that this is a slip of the pen for pennatula Schmidt. PORIFERA. II. 45 1887. Cladorhiza Nordenskioldii Fristedt, Vega-Exp. vetensk. Iaktt. IV, 455, PI. 25, figs. 56 — 59, PI. 31, fig- 25. 1896. Cladorhiza Nordenskioldii Lambe, Proceed, of the Roy. Soc. of Canada, Ser. 2, II, Sect. IV, 189, PL I, figs. 9, 9 a — f. 1901. Asbcstopliuna pennatula Topsent, Resultats du Vovage dn S. Y. Belgica, Spongiaires, 24 et 28, PL III, fig. 9 a— d. 1903. Cladorhiza pennatula Thiele, Archiv fur Naturgeseh. 1903, 385. 1903. Esperella plumosa Arnesen, Bergens Museums Aarb. 1903, No. 1, 11, Taf. II, Fig. 1, Taf. IV, Fig. 3, Taf. VI, Fig. 7. Slender, penniform ; the axis a little eompressed and the more or less long lateral branches in- serted in flie narrow sides. The axial skeleton with a rather powerful, close-spiculed exterior layer. Spienla: Megasclera styli in the axis o-68—i""", subtylostyli in the brandies and in the outer layer of the axis 0-52 — o^j""", irregitlarly sinuous, minutely spinulous tylostrongyla in the eoating of the stalk 0-05— o-ij/""" : mierosclera of three for vis, anisochelce palmata of two forms, the characteristic ones o-o/o — 0-0114""" . the large ones with the lower end polylobate 0-048 — o-o6j""", sigmata 0-021 — 0-024""". By the description of Schmidt cited above this species would not be recognizable; the recog- nition has only been possible by the description and figures of Topsent I.e. The species is erect and more or less penniform. It consists of an axis carrying for some way above a row of rather short lateral branches on either side. At the base the axis is somewhat thickened. All the specimens in hand are broken off below, but judging from the best preserved specimens and from stalk-fragments that must be of the lower part of the stalk, the stalk is here provided with more or less numerous, rather short lateral processes placed irregularly so as to form a kind of root. This part is presumably im- bedded in the mud, and the consequence is that the sponge is generally broken by the trawling, so that the root-part does not come up. Above the lower part the axis is regularly cylindrical and con- tinues so till the spot where the branches begin. Here it becomes somewhat compressed, in such a way that the lateral branches issue from the two narrow sides. There may be some difference in the length of the part carrying the lateral branches as compared with the total length. The greatest length of the lateral branches is up to 5 mm , in one case lip to j mm , but they may decrease in length and be so short as to be almost imperceptible. With regard to this fact the case may be somewhat different: either all the lateral branches may be long, or all short; or as well' long as short ones may be found, and then they are generally placed in such a manner, that the short ones are found below, the long ones above. One's first impression is that the lateral branches, when short, are damaged or more or less broken off. The case is, however, that the branches, when long, are quite thin and tapering outward, the thickness- is about o-i — o'2' n,n . The distance between them, which is, however, far from being equal, may be put down to about i mm . Now the more the branches are shortened, the thicker thev become, and the smaller becomes the distance between them. When shortest they form a series of quite slight, more or less confluent projections along either side, so that the the sides appear slightlv indented or sinuous. These quite short lateral branches show no trace of damage or fracture, and the spicules projecting from them are entire. Accordingly the feature cannot be owing to damage. loc f a y v a \ 46 PORIFERA. II. Neither do I think, however, that the question is of a constant difference as to form; on the contrary the fact of the long lateral branches being always thin and with few spicules, while the short ones are thicker and with more spicules, leads to the supposition that the feature is due to contraction, and I think that it must be explained in this way. An examination of a series of different individuals tends absolutely in this direction, and thereby we get a natural explanation of the always constant relation between the length and thickness of the branches. When the branches are long and thin thev are slightly curved upward. As before mentioned they are placed along each of the narrow sides of the axis, but thev are not arranged in any certain manner, and the distance between them may be somewhat different. Two branches are often found beside each other on the same side, but then thev are generally very close to each other, sometimes more or less coalesced; in other instances, however, the distance between them is somewhat greater. Sometimes the branches are, even pretty distinctly, placed in two rows on either side, and this structure is perhaps, strictly spoken, the most common one; but when the rows are very close to each other and the single branches are not placed directly opposite to each other, the feature is only seen indistinctly. When the branches are short, those that are thus close to each other seem to coalesce to one branch, so that we get only one thick spicula-bundle. At the upper end the branches become short and are turned upward, and they con- tinue in a fan-shaped manner round this end. In the lower part of the sponge, towards or quite up to the spot where the lateral branches begin, the stalk is surrounded by a more or less thick layer densely packed with particular spicules, which layer will be more thoroughly mentioned under the skeleton. This feature contributes to some degree to the thickening of the lower part. The stalk is generally straight, but sometimes it, or especially its lower part, may be irregularly bent and cracked. The largest specimen is of a length of ca. i8o mm , but it is broken below ; the part of it carrying lateral branches is of a length of a little more than ioo mm . The specimen is very slender, the stalk in its broadest part is only of a thickness of i — r5 mm , at the very base 2 mm . Some fragments of another specimen, which I suppose to have been upon the whole a larger one, are more robust, the stalk in its broadest part being 4 mm . All the specimens, as mentioned, are broken below, but to judge from stalk-fragments in hand, the sponge may grow to a considerable length. Thus we have stalk-frag- ments of a length of no mm , broken in both ends and carrying neither lateral branches nor root-like off-shoots. The thickest stalk-fragments are of a diameter of 5— 6' nm . The smallest specimen, which is likewise broken below, is of a length of 20 mm , and the stalk is o-t,™™ thick. The colour (in spirit 1 is white or yellowish white. The consistency is firm on account of the skeleton, but the sponge is fragile. The surface of the stalk and the branches is smooth without any projecting spicules; in the lower part of the stalk where the mentioned coating grows thicker, wrinkles and folds may be seen. While the stalk is smooth, also in the places coated with the mentioned layer, the root-part and especially the root-branches are shaggy, owing to the projecting of the needles of the coating layer. No bounded dermal membrane is to be observed. Outermost in the axis a dense layer of spicules is found belonging immediately to the skeleton of the axis. On the outside of the spicula-fibre of the lateral branches a thin layer of tissue is found closely filled with microscleres, and the same layer may also be found in the axis between the bases of the branches, as it may also be traced here and there in other places of the axis, but it is not bounded outward as a membrane. Neither oscula nor PORIFERA. II. 47 pores have been observed. From the arrangement of the skeleton it was to be expected that the pores might be found on the narrow sides of the axis between the branches, but here none were dis- covered. The possibility is perhaps not to be excluded that the lateral branches may act as oscula, in which case it would have to be supposed that in their most extended state they are hollow and connected with the canals of the stalk mentioned below under the skeleton; such a thing, however, has not been observed 1 ). The skeleton consists in the axis of parallel needles, closely connected with each other, and with the points turned toward the upper end of the sponge; accordingly the axis is firm and hard. It is, however, not massive, but pierced, throughout its length, by a number of canals separated by close-spiculed parts, and the whole structure is outmost surrounded by a close-spiculed layer. All the spicules are parallel to the longitudinal axis of the stalk. It is no easy thing to get a clear view of the number and arrangement of the canals, as whole transverse sections of the hard stalk are only to be obtained with great difficulty. There are always two rather large canals, one along the middle of either broad side of the axis; then the rule seems to be that on each side of these canals two small ones are found occupving, accordingly, the corner parts of the stalk; thus we have altogether ten canals, but sometimes there seem to be still more. Down in the stalk the structure is about the same, and the two chief canals may generally be recognized, but most frequently there seem here to be fewer canals and less regularity. In the thickened parts at the base of the stalk many more canals and more irregular ones are seen. To judge from observations on the few root-fragments in hand, the canals would seem also to pass into the root-branches. The stalk is sometimes a little twisted in the lower part, and then the canals follow the winding always following the longitudinal direction of the spicules. The skeleton of the branches consists of an axis, which may be more or less thick in proportion to the length of the branch, and is constructed of parallel spicules with their end turned outward; it is inserted in the narrow sides of the principal axis between the longitudinally running spicules of this axis in such a way, that the spicules of two lateral branches placed opposite to each other meet in the middle, and the spicules inserted in the principal axis are spread in a fan- shaped way in the longitudinal direction of this axis. As more thoroughly mentioned below under the spicules, the skeleton of the axis consists of styli with an admixture of subtylostyli especially in the outer part, while the skeleton of the branches consists of subtylostyli. The outside of the axis is, in its lower part, coated with a layer of varying thickness. It is rather firm and compact, showing a smooth surface with here and there some wrinkles and folds. It reaches towards, or almost quite up to the place where the lateral branches begin. It may be of varying thickness, from a scarcely per- ceptible crust to a rather considerable layer, the thickness being greatest towards the base, but also ') With regard to all the symmetrical, branched J/yra/t'-species — i.e. the genus Asbeslopluma — it is a fact that neither pores nor oscula have ever been mentioned in the literature. Either they are not mentioned at all, or it is stated that thev have not been found. Now several things might indicate that this fact with regard to some species is caused by the dermal membrane generallv being absent on the material obtained for examination. The specimens sometimes show ruined remains of a membranous character, especially at the base of the branches. With regard to the present species it is, perhaps, not improbable, that in the undamaged sponge the dermal membrane is, to a higher or smaller degree, suspended over the lateral branches, so that these are only partly free, and then pores and oscula are presumably found in this membrane. It is obvious that such a suspended thin membrane is easily destroyed, as the sponges in question is upon the whole from great depths and may be damaged in the trawl, or to a still higher degree in the swabs, with which instruments most of the individuals of the Ingolf-Expedition have been obtained. 4 8 PORIFERA. II. here somewhat varying. The greatest thickness was measured to about 2 ,nm . When the layer is thick it is frequently not of equal thickness all round, but the axis may be placed very eccentrically. In the thickened part of the stalk the thickening is often chiefly due to the outer layer, but the axis itself may also be thickened and the layer comparatively thin. The layer is quite compact showing no canals, and is easily separated from the axis itself. The skeleton of this layer consists of exceed- ingly densely interwoven, winding and finely spinulous tylostrongyla, which, although the layer contains no spongin, are only to be separated with great difficulty. The spicules of the other parts of the skeleton are united by a mass of spongin, quite clear under the microscope and consequently only to be seen with difficulty. On a transverse section the axis is seen to be slightly yellowish, while the sponginless coating of the stalk is whitish, and, when dried, gets a quite snow-white colour. Spicula: a. Megasclcra ; these are the spicules, partly of the skeleton proper, partly of the stalk- coating. The spicules of the skeleton are of two forms: styli, chiefly forming the skeleton of the axis, and subtylostyli, forming the skeleton of the branches, but also occurring in the axis. The styli of the axis may again be divided into two groups: long, slender, most frequently straight ones, and short thick, and curved ones; these two groups, however, are not sharply separated, but connected by tran- sitional forms, while there seem to be no transitions between the styli and the subtylostyli. The styli are fusiform and evenly tapering towards both ends; in the rounded end, moreover, a short, rather abrupt tapering is found, by which the styli are still more easily to be distinguished from the sub- tylostyli; this tapering is most marked in the thick forms. The other end has a short, somewhat stubby point. The length is o-68 — i mm , the thick ones generally not exceeding o-875 m,n , and sometimes going down to ca. o-6 mm . The thickness varies altogether from 0-015— o-032 mm ; for the two forms it may be stated to be about 0-015 — cvo2i mm , and 0-021 — o - 032 ,mn . Of the styli the thicker ones, to be sure, are found throughout the axis, but they are especially numerous towards the base. The subtylostyli are slender and straight, the head is only little marked and is placed a little below the rounded end. The point is short and often almost stubby. They are fusiform, tapering a little towards either end. The length varies from 0-52 — 075 mm , and the thickness in the middle is 0-009— O'oij" 1 "'. As mentioned above, the subtylostyli form the skeleton of the branches, and are also found in the stalk, especially in the outer layer. The spicules of the coating of the stalk are tylostrongyla, minutely and densely spinulous; they are sinuous and curved in very different manners. The head is rather distinctly marked, sometimes it is placed a little in on the needle; the other end is broadly rounded, and the needle is of about the same thickness throughout its length; sometimes it tapers a little towards the end. The length is between 0-05 and o-i37 mm , the thickness was measured to o-ooi — o-oo28 mm . The thinnest forms that have been observed, thinner than o-ooi mm , are so finely spinulous, that the spinules are almost not to be observed, and the very finest ones are perhaps quite smooth; I suppose them to be developmental forms, b. Microsclcra ; these are anisochelse palmatse of two forms and sigmata. 1. The charac- teristic anisochelae are small and of the structure peculiar to the subgenus. The shaft is curved. The two ends are exceedingly different; the upper end is provided with very large alse folding round on the side, the tooth is considerably shorter and narrower. When the chela is seen from the side, the axis is seen to bend round below like a hook, and alse and tooth are present in the common way; these parts are very narrow, but they are only to be seen with extreme difficulty, and so it is not PORIFERA. II. 40, possible to state their form exactly. When the chela is viewed with the smaller end turned directly towards the beholder, however, the alae and the tooth are distinctly seen together with the part of the axis between them (PI. X, fig. 4I1). These chelae are very small, their length is o-oio— o-oi 14""", and the breadth is 0-0057™™. 2. The large anisochelse are of a peculiar structure not quite easily understood. The shaft is about straight. The two ends are very different; the larger one is of the common Myca /^-structure, the alae are much refolded on the side, and the tooth is considerably nar- rower than the alae; a rather long tuberculum is found pointed downward. The form of this end is rather constant in one individual, but may be somewhat varying in different individuals. The variation consists in this end becoming longer in proportion to the total length, the lower edge of the alae bending much downward on their way outward from the shaft so as to form a far out-drawn lower corner, and the tooth becoming longer and at the same time narrower. The alae and the tooth may get so great a length as to reach the structures from the lower end of the chela. The smaller end of the chela is of a peculiar structure and shows a remarkable irregularity. When the chela is viewed from the front or from the side, some small teeth appear to issue from the lower end. Only when the chela is placed with the small end turned towards the beholder, it is possible to get a clear view of the structure. The shaft is then seen to have a narrow ala on either side; next three laps or teeths are generallv seen below, one on either side and one in the middle. The middle one is either un- divided or more or less split in two; most frequently it is completely divided, and then we get alto- gether four laps. This is the construction when it is regular, but frequently it is irregular and unsymmetiical, so that we see two laps on one side and only one on the other, or the two laps of the middle tooth are of unequal size. Also the alse of the shaft may be unsymmetrical, as upon the whole this end is subject to much variation. The laps or teeth are so thin and transparent, that, when the chela is not seen from the end, they are hardly to be observed. Unfortunately I have found no developmental stages of this chela, and so it is impossible to ascertain how the construction of the smaller end is to be interpreted, whether we have here real teeth, or one tooth divided into laps, or finally the lateral teeth are to be interpreted as belonging to the alas of the shaft. When two teeth are found in the middle this is surely the result of cleavage, which may also be seen from the fact that in such cases we find a median tuberculum the upper part of which is split. Also the lateral teeth seem to be provided with a tuberculum, but by this fact it is not proved, however, that they are independent teeth. Perhaps the developmental forms may solve this question. The length of the chela is between 0-048 and 0-063™™, tne greatest breadth is 0-022—0-027™™, and the thickness of the shaft is ca. o-oo4' n ™. As the length is proportionate to the mentioned variation in the form of the upper part, it is rather constant in one individual. The longer the upper end is in proportion to the total length, the shorter is the chela. 3. Sigmata; they have a comparatively little curved shaft, while the tolerably short ends are strongly bent in a hook-like way. A peculiar feature is that the shaft towards the bendings is compressed, and therefore a little broader, seen from the side. They are contort, most frequently a quarter of a turning, and they may therefore, by a slight glance and under small magnifying powers, recall small tylostyli, as observed by Schmidt I.e. That they may appear as tylostyles arises from the fact that the hook which is turned upward is not seen as a hook, but may give the impression of a swelling. Their length is o - 02i — 0-024™™, a "d tne thickness about The Ingolf-Expedition. VI. j. n - PORIFKRA. II. o - ooi4 mm . All the microsclera occur in great numbers in the tissue coating the branches and the axis of the part carrying branches; especially the small chela is found in enormous numbers. Embryos: In most individuals of this species embryos were found. They are oval or round, most frequently a little flattened, of a diameter of 0-5 — ca. i mm . They were frequently seen to be sur- rounded by a quite clear and transparent membrane. They occur in different, sometimes rather great numbers, and are situated in the mentioned axial canals. Most frequently they are placed in a single row in one of the principal canals (PL II, fig. 1), but they may also be found in the side canals, and they may be so densely crowded as to cause larger or smaller swellings (PI. II, fig. 4). With regard to spiculation they show some differences that are rather interesting. They have only sigmata and the small anisochelse. Sigmata seem to be the form of spicules first occurring, and in some specimens only these occur. In some specimens the sigmata, or most of them, were somewhat smaller than those of the developed individuals. While in the larger embryos sigmata and cheke were found in very great numbers, they were scarce in others, and in some of the embryos no spicules seemed to be present at all. Remarks to the synonymy. I have been able by examination of one of the specimens of the Barents-Expedition to identify as pennatula the species mentioned by Vosmaer I.e. as Cladorhiza bihamatifera. Vosmaer mentions it as a difficult thing to get a clear understanding of the large chelae and says, — I now believe that they are to be considered as -&/^/7«-auchorates, where all the teeth are fully developed, and not two with one rudimentary . What is meant by this phrase is unintelligible, as the larger end of these chelae is of the same structure as in all common Mycale- chelae. — Of Armauer Hansen's material I have examined a few specimens which proved to be prima tula, but under his bihamatifera several species are mingled together; from the figures it may however with rather great certainty be decided, which of them belong to the present species. Of Fristedt's Cladorhiza Nordenskioldii I have examined a fragment of the type specimen, which proved it to be pennatula; Fristedt must have overlooked the small chelae. Also Lambe I.e. must have overlooked these chelae, as the Cladorhiza Nordenskioldii mentioned by him is certainly identical with pennatula. It is easily understood that he has overlooked them, as he has had onl) - the lower part, where the small chelae only occur much scattered. Finally the E. plumosa established in 1903 by Arnesen I.e. is identical with A. pennatula, which fact I have been able to decide with certainty, as I have examined a fragment of one of the type specimens. In the quite insufficient description no account is rendered of the two forms of cheke; the length of 2"7 mm given for the megascleres must be due to an erroneous measuring; in the specimen examined by me I have found none larger than o'95 mm . Locality: Of this species the Ingolf-Expedition has obtained a great number of specimens. Station 6, 63 43' Lat. N., 14 34' Long. W., depth 90 fathoms; station 39, 62 00' Lat. N., 22 38' Long. W., depth 865 fathoms; station 40, 62 00' Lat. N., 21 36' Long. W., depth 845 fathoms; station 67, 6i° 30' Lat. N., 22° 30' Long. W., depth 975 fathoms; station 68, 62 06' Lat. N., 22 30' Long. W., depth 843 fa- thoms; station 78, 6o° 37' Lat. N., 27 52' Long. W., depth 799 fathoms; station 81, 6i° 44' Lat. N., 27 00' Long. W., depth 485 fathoms; station 94, 64° 56' Lat N., 36 19' Long. W., depth 204 fathoms; and station 144, 62 49' Lat. N., 7 12' Long. W., depth 276 fathoms. On station 78 the greatest number of specimens PORIFERA. II. 51 were taken. The stations are situated between the Faroe Islands and Iceland, south of Iceland and in the Denmark Strait at the eastern coast of Greenland. The depths vary from 90—975 fathoms; the bottom temperatures on the stations were from i°6 til 7°o C. Further I have before me one speci- men from the northwestern coast of Norway, Lyngen, depth 160 fathoms (O. Nordgaard). Gcogr. distr. The species is further known from the following localities; off Bukenfjord and Haugesund, depth 106— 115 fathoms (Schmidt 1. c.) ; Tronhjem Fjord (Arneseu I.e.); the Barent Sea, depth 220 fathoms (Vosmaer); the east coast of Greenland, depth 130 fathoms (Fristedt); the Gulf of St. Lawrence, depth 200 fathoms (Lambe). Accordingly the species is a northern one, and has hitherto been found from about 23° 20' Long. E. to about 65 Long. W., and between 50 and 74° 10' Lat. N. As is commonly the case, it reaches considerably farther south at the American coast than at the Euro- pean; thus at the coast of Norway it has only been obtained to about 59 Lat. N. 2. A. bihamatifera Cart. PI. II, Figs. 7—8. PI. XI, Fig. 1 a— g, Fig. 2. 1876. Espcria cupressiformis var. bihamatifera Carter, Ann. Mag. Nat. Hist. Ser. 4, XVIII, 318, PI. XIII, fig. 14, PI. XV, fig. 34 a-b. Sliorter or longer lateral branches pass off from the axis all round. The axial skeleton is dn the thickness about O'ooi — 0-003™'". b. Microsclera are anisochelse palmatse of two forms and sigmata. 1. The characteristic anisochelse are those typical for the subgenus, and they are of quite the same form as those in pennatula. Their length is o-oio— o-on""", and their breadth is ca. 0'005' nm . 2. The large anisochelse are also af a similar form as in the preceding species; the shaft is straight; the larger end is not subject to the variations in form and size found in pennatula, but makes always about half the length of the chela; the alse are folded far round on the side, and their lower edge is rather straight without forming a far drawn out lower corner. The tooth is about as long as the alse and is somewhat narrower than these; at the end it is cut off with rounded corners; a long, downward pointed tuberculum is found. With regard to the smaller end of the chela the description given under pennatula will almost entirely hold good; the only difference being that this end in proportion to the size of the chela is smaller than is most frequently the case in pennatula; also it is generally less irregular, and the variation consists chiefly in the fact that the middle tooth is either whole or split. The length is 0-051— oo6i mm , the breadth 0-020 — o-o25 ,nm , and the thickness of the shaft is about o-oo5 mm . 3. Sigmata; these are of the same form as in pennatula with only little curved shaft and short ends, bent in a hook-like way. The shaft is likewise compressed or sharpened like an edge inward towards the bendings, and they are contort, most frequently a quarter of a turning. The length is 0-018— o-02i mm , the thickness in the middle is ca. o-ooi mm . The microscleres occur in large numbers in the dermal membrane and in the tissue of the part carrying the branches. As will have been seen, this species is very closely allied to the preceding one, and differs r . PORII-ERA. II. 54 from it especially by the facts that the branches are polyserial and the spined tylostyli of the coating layer more pointed, and these two characters are constant and are found together in all the material I have examined. It will also have been seen from the description that the skeleton of the axis is constructed in a somewhat different way. After Carter's descriptions and figures I regard the iden- tification as certain, as both the spicula-figures, especially that of the large chela, agree very well, and also the figure of the exterior of the small fragment Carter had show that the question is of a species with branches arranged polyserially. Of Armauer Hansen's figures of exteriors those on PI. VII, figs. 2, 3, and 15 might perhaps be bihamatifera, but as it is said in the text that only one of all the specimens had sigmata, the question is more likely of the species lycopodium. The question cannot be decided with certainty, as the fact that sigmata of two different specimens are figured, both on PI. Ill, fig. 5, and PL IV, fig. 2, shows that the quoted statement is wrong, and I have also examined two specimens, which were both of them pennatula and consequently both provided with sigmata. Locality: Station 15, 66° 18' Lat. N., 25 59' Long. W., depth 330 fathoms (bottom temperature -f-o c 75C); station 59, 65 00' Lat. N., n c 16' Long. W., depth 310 fathoms (bottom temperature -ho°iC); station 126, 67° 19' Lat. N., 15 52' Long. W., depth 293 fathoms (bottom temperature -=-o°5G); station 138, 63 26' Lat N., 7 56' Long. W., depth 471 fathoms (bottom temperature ^-o°6C); altogether eight specimens. The stations are situated in the Denmark Strait, north and East of Iceland, and north of the Faroe-Islands, and they are seen all to belong to the cold area with negative bottom temperature. It is of interest to see that this species, which is so closely allied to the preceding one, from which it differs only by slight, but constant characters, occurs exclusively in localities with negative bottom temperature. Gcogr. distr. With regard to the specimens of the present species from the Norwegian North- Atlantic Expedition the more particular localities are not known; if the species are represented in the material, it must be supposed to have been taken on one of the stations in the cold area. The locality is also wanting for the specimens of Carter, but on account of other sponges in the same jar he thinks that the locality may possibly be in the western entrance of the British Channel. This is probably not the case, however, as the species is a native of colder bottom, and I suppose that Carter's specimens originate from one of the cold stations of the sPorcupine:. 3. A. furcata u. sp. PL II, Figs. 9—10. PL XI, Fig. 3 a — h. The axis slender, diclwtomously branched once or several times. The lateral branches very short, placed all round, only on the upper ramifications. The axial skeleton divided into fibre-like parts, out- most a thick layer of spicules. Spicula: Megasclcra styli in the axis o-jp—o-6f'"", subtylostyli in the branches and outmost in the axis, 0-268— o-j 6""", curved, finely spinulous tylosfrongyla in the coating of the stalk 0-068 — o-og $'"'"; inicrosclcra of three forms, anisochela- palmata of tzvo forms, the characteristic ones o-o/o— 0-0/4""". t,lc large ones with unsplit or split lower tooth 0-044 — 0-054""" '. sigmata o-o/j—o-o/?""". This species is of a very slender form; it begins below with a stalk that gradually branches dichotomously. The most ramified specimen branches three times, so that the two branches formed PORIFERA. II. 55 111 the first instance divide again, and the new-formed branches divide also. In one specimen one branch divides into three, sending off two lateral branches while the principal one itself continues in the middle. In another specimen a coalescing of two stalks has taken place; as the lower part of the specimen is wanting it cannot be seen, whether the two branches belong to one individual, or two different individuals are coalesced. The stalk is somewhat widened below and has been attached to some firm object. The stalk may be straight or somewhat curved, and it is about cylindrical. On the ramifications lateral branches are found more or less extensively; they are generally only found on the outmost ramifications, sometimes also some way down the branches below the last division. Thus in the smallest specimen, which has only two branches, they are found some way down the stalk The lateral branches are small, almost scale-like and most frequently very much directed upwards, sometimes almost quite adpressed. They are arranged in several rows, but very irre- gularlv, so that the rows in some places are close together, while at other places the intervals are greater. The axis is slightlv compressed in the parts carrying lateral branches. The branches end with a compressed part forming an extended, and on account of a little notch somewhat heart-shaped, head. Perhaps the question is only of a beginning new cleaving. In a single fragment the last ramifications end without this head, and this is perhaps a specimen in which the growth has ceased. The stalk has a thin coating of the common nature, and this layer generally reaches far up, often to the last, or last but one, division. The largest specimen in hand, the above mentioned most richly branched one has a height of 140""", the stalk to the first division is 35 ram long. The smallest specimen, which is only divided once, is 6$ mm high. The species, as mentioned, is very slender, the stalk of the largest specimen has only a diameter of 2 mm , and farther up the thickness is 1 — i'5 mi ". The lateral branches do not reach more than i mm in length. The consistency is of the common firmness. The colour (in spirit) is whitish yellow to light brownish; the coating layer of the stalk is always a little darker. The surface is smooth, but on the part with branches it appears under the microscope to be shaggy from the projecting chelae. No distinct dermal membrane was seen; outermost in the skeleton a dense layer of spicules is found, and outside of this a thin layer of tissue, copiously provided with micro- scleres. Oscula and pores were not observed. The skeleton. The skeleton of the axis consists of closely united, parallel needles. Through the axis run a number of canals, which in the ramigerous part seem to be arranged in a more or less ringlike way, and are separated by narrow parts of spicules, as also the fibres of the lateral branches, where such are found, pass in between them. Lower down in the stalk the canals are not regularly- arranged, so the separating spicula-parts are also here, when seen in transverse sections, irregularly sinuous. Accordingly, the skeleton of the axis is by the canals divided into fibres or narrow, fibrelike parts. Outmost a dense layer of spicules is found, which is most frequently rather easily loosened on the stalk below the ramigerous part, while on this part such is not the case, and here where the lateral branches are inserted, the needles of this layer do not exactly run in the direction of the longi- tudinal axis. In the lower part of the stalk the axial skeleton is twisted in a spiral manner. The skeleton of the lateral branches consists of bundles of spicules ; they are inserted between the spicules of the axis in the common way, and reach to, or about to, the middle. The skeleton of the axis consists ofstyli, among which in the outer layer of spicules shorter subtylostyli are intermingled; the skeleton of 56 PORIFERA. II. the lateral branches consists of short subtvlostyli. The skeleton of the coating layer of the stalk consists of closely interwoven, finely spinulous tylostrongyla. The spicules of the axis are united by a clear mass of spongin. Spicula : a. Megasclcra; these are the styli of the axis and the subtvlostyli of the lateral branches, besides the spicules of the coating layer of the stalk. The styli in the axis have in this species no abrupt tapering towards the head-end, and as the subtylostvli show most frequently an almost indiscernible swelling, the difference between them is chiefly to be sought in the size. The styli, to be sure, vary somewhat in form and size, but they cannot here be said to be divided into two groups. They are straight, or slightly, only rarely a little more highly, curved; they are slightly fusi- form with the greatest thickness in the middle. The point may be a little varying, but is always short or rather short; most frequently it is bounded by straight lines. The length is 0-39 — o-65 mm , the extreme measures, however, occurring rarely. The thickness, which has no definite proportion to the length, is between o-oio mm and o-024 mra . The subtvlostyli are straight, only sometimes quite slightly curved. They are only a trifle thicker in the middle than towards the ends; the head, which is placed a little down on the needle, is generally a scarcely perceivable swelling; the point is short, but bounded by straight lines. The length is 0-268— 0-36""", the thickness is 0-007 — o-on mm . The spicules of the coating of the stalk are minutely spinulous tylostrongyla; the}- are more or less irregularly curved, most frequently to a rather slight degree. The head is round and distinetlv developed, they do not taper much towards the opposite end, and this end has a little swelling, so that in form they approach tylotes. They are smaller than in the preceding species, the length is o-o68— o-095 mm , and the thickness about o-ooi mm , a little more or less. b. Microsclera are anisochelse palmatse of two sizes and sigmata. 1. The characteristic small anisochelse are of the type of the subgenus, and are of the same form as in the preceding species; they are, most of them, ooio mm long and o-oo5 mm broad, but chelse may be found reaching to a length of o-oi4 mm . 2. The large anisochelse are also of a similar form as in the two preceding species. The shaft is straight; the larger end is about half so long as the whole chelse; the tooth is considerably narrower than the alee, it is broadest below, and rather straight cut off with rounded corners or sometimes more rounded; a long, down- ward pointed tuberculum is found. The smaller end is more regular than in the preceding species, and its form is more like that of the common type. The shaft has a pair of short alas, rather broad above, and forming together a triangle; then there is a curved tooth of similar size, most frequently, however, a little shorter than the alse. As the tooth is in a rather oblique position to the shaft, it appears always somewhat shortened, when the chela is seen exactly from the front, and its curved form is also seen. Accordingly, when the tooth has this form, the structure of the smaller end is quite normal; the tooth, however, is often split into two lobes, and the splitting may be more or less pro- nounced; lateral lobes, however, are never found. Also here the tooth is so thin and transparent, that a clear view of the form can only be got by regarding the chela from the end. The length is 0-044 — o-054 mm , the breadth about 0'02i ram , and the thickness of the shaft is about o-oo4 mm . 3. Sigmata are of the same form as in the preceding species with the same edge-like expansion of the shaft towards the ends, and they are also contort. The length is 0-015 — o-oi7 mm , and the thickness about Q-OQjmm aj] forms of microsclera occur in great numbers in the tissue. PORIFERA. II. 57 Embryos. In this sponge embryos were most frequently found; they occurred partly in the upper ramifications, partly somewhat lower down. They were, as far as I could see, situated in the canals just inside the outermost layer of spicules, but each embryo appeared to be inclosed in a cavity of its own, and the places in which they occurred were a little swollen and thus fusiform. The embryos are roundish or oval, and have an average diameter of o'3' nm . In contradistinction to the embryos found in pennatula, both megascleres and microscleres are found here. The megascleres are all subtylostyli; they are similar to those in the grown individual, but are often a little more curved, and the head may be marked off in different ways; they have also on an average a somewhat longer point. Thev are smaller than in the grown sponge and have an average length of o-2o8 mm . Of micro- scleres only the small chela and sigmata are found; both of them are fully developed, and they show a peculiar and surprising feature, being both a little larger than in the grown sponge. Thus sigmata reach a length of o - 02i mm , and the chelae are 0-0114 — o-oi43 mm long. According to this it must be sup- posed that the first formed of these chelse and sigmata are a little larger than the final form, which appears later. Chelae and sigmata are present in great numbers. The embryos seem here to leave the sponge by a bursting of the wall, the outer layer of spicules being in several places swelled out by the embryos underneath, and in a few cases a hole and an empty cavity are seen. Locality: Station 101, 62 23' Lat. N., i2°05' Long. W., depth 537 fathoms (bottom temperature -r-o°7C), one specimen. Further it has been taken on 62 53' Lat. N., 4 14' Long. E., depth 450 fathoms, one specimen, and east of Iceland without any statement of depth, five specimens (Ad. Jensen, the cruise of the « Michael Sars 1902). The localities are situated east and northeast of Iceland, and at the coast of Norway. With regard to the two last localities no bottom temperature has been given, but they are situated in the cold area, and thus this species is also a native of the cold bottom. Note. Of Armauer Hansen's figures to Espcria bihamatifrra (The Norwegian North- Atlantic Exp.) I am inclined to suppose, and I think there is great reason for supposing, PI. VII, fig. 4, and especially PI. Ill, fig. 5 to be the present species. As will have been seen, the species of this subgenus are distinguished by a peculiar coating layer on the stalk. At first one might be inclined to think that the question was of a separate sponge incrusting the stalk of these sponges, as is also pointed out by Top sent by the men- tioning of pennatula and Bclgica I.e.; but the constant occurrence of the layer, and the difference of its spicules in the different species proves it to be a formation belonging to the sponge. Those species of the subgenus of which rather intact specimens have been examined, show a formation of roots. This formation is connected with the fact, that they are no doubt sunk into the bottom of the sea, as it would seem, with a very long part of the stalk. I suppose that this is also the reason why they are provided with the coating layer. The species furcata, however, is an exception, as it is not sunk into the bottom, but is attached with its base. Nevertheless it has the coating layer, but it is very thin and shows the peculiarity that it reaches very far up, often to the last ramifications. The In^olf-Expedition VI. 2. 8 5« PORIFERA. II. Lycopodina n. subg. Lateral branches issuing all round from an axis, or the brandies collected in the upper end of this axis; sometimes the lateral branches are more or less coalesced. The skeleton consists of a spicula- axis, and the branches are supported by fibres inserted in the axis, or in other ways connected with it. Spicula: Megasclera styli or snbtylostyli; microsclera: the characteristic anisochete palmate are small, the ate of the larger end pass down quite to the opposite end, which is rather broad ; to these spicules forcipes are most frequently added. 4. A. cupressiformis Cart. P1.II, Figs. 11 — 14. PL XI, Figs.4a— f, 5. 1874. Esperia cupressiformis Carter, Ann. Mag. Nat. Hist. Ser. 4, XIV, 215, partim, specimen in inter- clusione commemoratum exclusum, PI. XIV, fig. 16 a — i, figs. 17— 18, PL XV, fig. 37. 1885.? Esperia bihamafifera Armauer Hansen, The Norwegian North-Atlantic Exp, XIII, Spongiadse, partim PL VI, fig. 1, PL VII, fig. 1. 1886. Esperella cupressiformis var. robust a Levinsen, Dijmphna Togtets zool. bot. Udbytte, 364, 18 a, Tab. XXIX, Fig. 10- 1 1, Tab. XXXI, Fig. 7— 14, i6a,b,c. 1887. Cladorhisa cupressiformis Fristedt, Vega-Exp. vetensk. Iakttag., IV, 457, PL 25, figs. 66— 69, Pl-3 1 * %• 2 7- 1900. Esperella Fristedtii Lambe, partim, specimina dna e tribns commemoratis, Transact, of the Royal Soc. of Canada, Ser. 2, VI, Sect. IV, 21, PL I, figs. 2, 2 a.— e. Irregularly situated short lateral branches pass off all round from the axis, or the brandies coalescing to a curled surface; sometimes all the upper part or only the uppermost portion of it leaf- shaped. The skeleton consists of a spicula-axis, the ramigcrous part is supported by an irregular skeleton, from which the fibres of the lateral brandies pass off, but they are not inserted in the axis. Spicula: Megasclera subtylostyli or styli 0-35— 0-84""" : microsclera of two forms, the characteristic anisochete palmate 0-023 — 0-025""", forcipes 0-038 — 0-046'""". This species is of a slender, erect form. Below it consists of a more or less long stalk, all but cylindrical, which is most frequently one fourth of the total length. The npper part is somewhat thicker than the stalk and carries a number of short lateral branches, placed irregularly, and issuing all round. These branches may be very short, so that they almost do not project over the surface, or there may between them, or instead of them, be found low ridges especially running longitudinally, and then the upper part shows only a highly .wrinkled, folded, or curled surface; but in most cases the projections are formed as cylindrical, a little conical branches rising with a broad base from the axis. They reach at most a length of about 3'™. Sometimes the sponge is above widened to a small leaf-shaped part (PL II, fig. 11), and one specimen consists of a quite short stalk passing into a broad, rather thin leaf with a grooved and wrinkled surface (PL II, fig. 12). Below the sponge is attached by a somewhat widened part of the stalk. The specimens in hand from the territory treated here are torn off from the substratum, but specimens from the Kara Sea are attached to shells (Astarfe sp), worm-tubes (Spiocha-topterus typicus and especially Pcdiuaria hypcrborca), and to pebbles. The largest PORIFERA. II. 59 specimen (from the Kara Sea) has a length of ca. 135'""', the stalk is 26"™ long, the greatest thickness is 7 mm , and the stalk is ca. 2 mm thick. Then we have specimens of all sizes downward, the smallest specimen is 15™°" high. The mentioned leaf-shaped specimen has a height of jj™™, and a breadth of ca. 70™'", its stalk is only \7> mm long. The consistency of the upper part of the sponge is softer than in the preceding species, the stalk is hard. The colour (in spirit) is whitish gray to whitish yellow. The surface, apart from the nature described above, must be said to be smooth, only in the ends of the lateral branches bundles of spicules project. 1 11 the specimens in which no lateral branches pro- perly so called are found, but only longitudinal ridges and irregular projections, spicules project through these, and thus these individuals get a more shaggy appearance. Under the microscope also other parts of the surface may appear shaggy from the projecting chela;. The upper part of the stalk is smooth, but it becomes shaggy towards the base. A dermal membrane ma}- distinctly be observed, and is easily isolated; it is thin and transparent and highly filled with chelse, on the other hand there is no dermal skeleton proper, but the membrane rests on the skeleton below, and when it is isolated, needles may be seen scattered in it. Pores have not been observed in the dermal membrane. Oscula: the mentioned lateral branches act, no doubt, as oscula; the fact is, that these branches are not solid, but are chiefly formed by the dermal membrane, which is here supported by spicules parallel to the longitudinal axis of the branches. If a branch is cut off it is seen to be hollow, and leaves a hole; on the other hand, an osculum is not distinctly seen at the point of the branch, as the spicules are here closer joined. As the branches are very numerous, and as pores have not been observed, it might be supposed that also the inhalent system was connected with the branches; it is, however, more prob- able that the pores are closed. The skeleton. The skeleton of the axis consists of close-lying spicules parallel to the longitu- dinal direction. The axis, however, is not quite compact, the spicules being collected into close-lying fibres; in the interstices an irregular reticulation of spicules is found, which spicules are placed obli- quelv to, or across of, the longitudinal direction; sometimes, however, this feature is little prominent, and then the axis is more compact. It continues from the stalk up through the sponge, quite to its uppermost end, and it keeps about the same thickness. The outer skeleton, which supports the upper part, consists of a quite irregular net-work of spicula-bundles and scattered spicules, with short fibres here and there. As mentioned, the lateral branches are supported by spicules apparently forming a fibre, but really only supporting the wall of the branch; these spicules do not reach to the axis, but pass only into the other skeletal net. In the lower part of the stalk, where it is shaggy, spicules are woven into it, projecting more or less horizontally, and over the surface. A coating with special spi- cules is not found. In the mentioned leaf-shaped specimen the skeletal structure has been modified in an interesting manner; the short stalk continues as such only a short way into the leaf, and then it is lost. It does not cease, however, but is, as it were, spread in the plate, rather close-lying fibres, radiating towards the edge, running through the plate; these fibres correspond to those of the axis, and they are, like those, connected by spicules and spicula-bundles, which are placed transversely or obliquelv in the interstices. This whole structure forms a thin skeletal plate in the middle of the leaf- shaped part, and on both sides is found a tissue with a skeleton constructed in the same manner as the skeleton outside the axis in the other individuals. In the axis the spicules are united by a rather s* 6o PORIFERA. II. copious, but white and clear mass of spongiu, which is most developed towards the base; in the skeleton outside of the axis, on the other hand, no spongin seems to be present. Spicida: a. Megasclera are long, slender subtylostyli, sometimes styli. They are straight, or slightly, most frequently somewhat irregularly curved. The head-end is only very slightly swollen, the opposite end tapers evenly to a rather long point which is often somewhat more abruptly pointed at the end. The needles are here of only one kind, and are the same in the stalk and in the other skeleton, the only difference being that in the lower part of the stalk they become gradually shorter, and the needles that here project and make the stalk shaggy are also short. These short needles are generally more highly curved, and are most frequently styli without any head-swelling, but they cannot be separated from the others as a particular kind. The length is between ca. 0-35 and o - 84 mm , but in these measures are also included the needles occurring towards the base of the stalk; if the lower part of the stalk is excluded the lower limit of the length may be put to about o - 5 mm , and in a spicula- jDreparation in which no sample from the lower part of the stalk has purposely been added, the length of the needles therefore will be found to be ca. 0-5 — o - 84' nm , and the shorter ones will only occur more rarely. The thickness varies from ca. o - oo8 — o-oi4 m,n ; the longest ones are not the thickest. Finer, to quite fine developmental forms are seen in small numbers, b. Microsclera ; these are of two forms, aniso- chelse palmatse and forcipes. 1. The anisochelse are of a form characteristic of the subgenus; the larger end is of a similar form as in the preceding subgenus; the alee are very large and reach far down, quite down to the lower end, and there is a considerably shorter and narrower tooth. The smaller end is of a peculiar structure, not easily understood. When the chela is lying on the side a pair of small points are seen at this end, one at the outer end of the axis, the other a little higher up. The best view is got when the chela is seen in such a way as to turn the smaller end directly towards the beholder (PL XI, fig. 4d), and then it is seen that alse and tooth are present as usual. The peculiar feature is that the alae do not run along the shaft in the common way, but are placed almost transversely on it. The axis then continues with a slight bend, and at the end of it the tooth is placed parallel to the alse; it has a distinct tuberculum. When the alse and the tooth are seen from the side, they are seen as the mentioned two points. When the chela is viewed from the front under sufficiently high magnifying powers, a pair of refractive ridges are seen about where the alae of the upper end cease; these ridges are the upper part of the alae of the lower end where they go off from the axis ; they are here the most narrow, but downward they become gradually broader, and fold round on the side; the whole thing might be described by saying that the upper outer corner of the ala had been cut away by a large cutting rounded inward. The tooth, which is also somewhat curved, has a form corresponding to that of the alse, being also most narrow above, but increasing in breadth down- wards, and thus showing the same cutting. The folded sides of the alse and the tooth meet on the side leaving only a narrow opening between them ; as a consequence of the form the lateral edges are here short. The described form of the alae and the tooth, together with their position with regard to the axis, is the cause why they appear as two points when viewed from the side under small magni- fying powers. The anisochelse are 0-022 — o-025 mm long 1 ) and ca. o , oi2 in,n broad. Developmental stages ') A few chelae were seen of a length of o-oi4 mm , but they, no doubt, belong to the embryos present in the sponge, see below under Embryos. PORIFERA. II. 6 1 of this chela were found abundantly on all stages from so fine ones, that they are hardly to be seen. Levinsen I.e. has already given an account of the development of this spicule. — The construction of the lower end of this chela has never been correctly understood, and neither Carter's nor Fri- stedt's figures are correct. Levin sen, on the other hand, has given good figures, I.e.; the lower end on PI. XXXI, fig. 7, cannot, however, appear as it is figured, when the chela is seen in the stated position, but only, if it is seen considerably more obliquely from one end or the other. Neither has Levin sen clearly understood that the question is of the common parts, alse and tooth, in a somewhat modified shape. 2. Forcipes. These are of the common form with a round bend above; the legs are parallel or more or less diverging, and end in a small swelling; the upper part between the legs is somewhat thickened, and appears, especially when the forceps is seen from the side, as a tubercle- like swelling. The length is 0-038 — o - 048 mm , and the thickness above is ca. o-oo2i mm ; the thickness of the middle of the legs does not exceed o-ooi4 mm . The chelse occur in enormous numbers; they are partly found in the tissue, but especially in the dermal membrane, in which they are exceedingly close packed, so as to render it quite shaggy ; they appear always to be turned with the larger end outward. In contradistinction to the chelse the forcipes are limited in their occurrence, being only found in the point of the sponge, as has been pointed out by Levin sen; in this respect it is an interesting fact that in the mentioned leaf-shaped specimen the forcipes are found throughout the leaf-shaped part, which fact would seem to prove this whole part to correspond to the point of an individual of the common form. Embryos. In several individuals of this sponge embryos were found. They are situated in the tissue in very great numbers; they are globular, the larger ones a little oval, and they are rather small; the size is very varying, and was measured from 0-05— o-27 mm . They are in the tissue surrounded by a membrane, and they appear each of them to be situated in a little cavity. Their spiculation presents some points of interest. They are provided with both megascleres and microscleres. The megascleres are straight or often rather strongly curved tylostyli and subtylostyli, most frequently with rounded end; they are often more or less irregularly formed, and besides quite irregular forms occur, small short styli, strongyla, and other forms, as also small, more or less irregular siliceous globules. The greatest length measured of the needles was o-i2 mm , and they may reach a thickness of ca. o-oo7 mm , but they occur in all degrees of thinness, down to exceedingly thin ones; in the same embryo, however, they are always of about the same thickness. They are only found in small numbers, 12—16 needles were counted in each embryo. They are always arranged in a particular way in the embryo, viz. as a bundle placed radiately with one end towards the centre and the other towards the periphery; this bundle may per- haps be interpreted as the first indication of the axis. The needles of the bundle are turned in differ- ent ways, some of them have the head-end turned inward, others outward. The microsclera are anisochelae occurring in no small numbers, as well fully developed ones as developmental forms, but they are considerably smaller than the chelae of the grown individuals, their length being only o-oi4 mm . In the smallest embryos no spicules were seen. Observations on the synonymy. In spite of the peculiar and evidently very diagrammatic figure of the exterior found in Carter, it may no doubt be regarded as certain that the question is of his species. If, for instance, his figure is compared with my figure of the exterior PI. II, fig. 14 it will be 6 2 PORIFERA. II. seen tliat this latter, if it were drawn in the same way as Carter's figure, would get a quite similar appearance. The other form mentioned in a parenthesis, to which belong the figures 16, g, h, and 19, a, b, I suppose, on the other hand, to be A. infundibulum Levins. Of Armauer Hansen's figures the cited ones may with great probability be referred here. The two varieties enumerated by Levin sen under his c?tpr ess/for mis are certainly two well separated species, and only var. robusta belongs to the present species, while var. lycopodium is a separate species. Of Fristedt's Cladorhiza cupressiformis I have examined a type-specimen; the species is identical with the present one, and when Fristedt says that his species is wanting forcipes, he must have overlooked them, I suppose, on account of their being only found in the upper end; the fact is that they are really found in his specimen. With regard to Lambe's species Esperclla Frist cdtii the facts are rather peculiar; I have examined a frag- ment of one of his specimens. First this fragment proved to have forcipes, which must accordingly have been overlooked by the author; but then this fragment did not belong to this species, but to the following one, and accordingly it evidently belongs to the specimen that Lambe mentions sepa- rately. According to the description and the figures there can now be no doubt that the two other specimens are A. cupressiformis. The spicules mentioned bv Lambe and figured in fig. 2, d and e, also corroborate this view, as they are exactly the embryonal spicules mentioned above under the embryos. When Lambe says that his species deviates from cupressiformis by not having forcipes and by its outer form, the reason of the first fact is that forcipes have been overlooked, and the latter fact cannot well be decided from Carter's diagrammatic figure of the exterior. When he further mentions differ- ences in the form of the chelae this statement is of no consequence, as neither Carter's figures nor those of Lambe himself are correct; Carter's, however, are far the better ones. Locality: Ingolf, station 3, between the Faroe Islands and Iceland, 63 35' Lat. N., io° 24' LongW., depth 272 fathoms, and at East-Greenland on the following localities: 72 40' Lat. N., 20 c 00' Long. W., depth 100 fathoms; 72 27' Lat. N., 19° 50' Long. W., depth 120 fathoms; and at the south coast of Jame- son's Laud, depth 10—60 fathoms (The East-Greenland Expedition 1891 — 92); five specimens in all. Geogr. distr. The species was taken by the « Porcupine between Scotland and the Faroe Islands, at depths of 384, 363, and 632 fathoms, with the following respective bottom temperatures : -4- o°8, -^o°3, and -=- o°8 C. Then it has been taken in the Kara Sea, depth 51—81 fathoms (Levinsen); west of Taimur, 76 18' Lat. N., 92 20' Long. E., depth 40 fathoms (Fristedt); the Baffin Bay at depths of 200 fathoms and 60 — 100 fathoms (Lambe). Thus the species is known from a territory between 70 Long.W. and 92 Long. E., and between ca. 6o° and 76 Lat N., with a bathymetrical range from ca. 40 — 632 fa- thoms. The species seems chiefly to be a native of the cold bottom, as most of the mentioned locali- ties, or perhaps all of them, have a negative bottom temperature. Only the Ingolf-statiou 3 is a sure positive locality with a bottom temperature of o : 5C, but then it is also of some interest to notice the fact that the mentioned deviating leaf-shaped specimen is obtained just on this locality. 5. A. lycopodium Levins. PI. II, Figs. 15—17. PL XI, Figs. 6 a— d, 7. 1885. Espcria biliamatifera Armauer Hansen, partim, The Norwegian North-Atlantic Exp. XIII, Spon- giadce, PI. 3, figs. 3, 4. PORIFERA. II. 63 1886. Esperella cupressiformis var. Lycopodium Levinsen, Dijmphna Togtets zool.-bot. Udbytte, 364, 18 b, Tab. XXIX, Fig. 12, 13, Tab. XXX, Fig. 15, 16 d. 1900. Esperella Fristedtii Lambe, partini, specimen uimm e tribus commemoratis, Transact, of the Roy. Soc. of Canada, Ser. II, VI, sect. IV, 21, PI. I. fig. 2 f — h. The axis slender with closely placed lateral branches issuing all round. The skeleton consists of a spicula-axis divided into fibres, between which the fibres of the lateral branches are inserted; outside of I lie axial fibres only a few scattered spicules. S fie 11 la: Megasclera styli 0-238 — 1-5"""; uiicrosclera of two for/us, the characteristic auisochelcr palmatce 0-014 — o-oij""", forcifes 0-050 — 0-056""". In outer appearance this species reminds somewhat of A. bihamatifera. It is of a slender, erect form; below it has a quite short stalk. The other part is set with thin lateral branches issuing all round. In different individuals the branches may be of different length, which does not, however, ex- ceed 3 — 3 - 5' nm . The question is also here, I suppose, of contractibility. In a single specimen in which the branches are short, they are, as it were, somewhat coalesced at their bases, so that this specimen, as to its exterior, may somewhat remind of the preceding species. One specimen is of a peculiar appearance, showing no branches, but having all the part that in other specimens carries branches closely set with projecting needles which are, however, collected into bundles on the lower part. In a transverse section it is seen, however, that the projecting spicules, which are apparently evenly distributed over the surface, are bundles, radiating from the middle towards the surface, and sprea- ding to some degree so as to be spread in a penicillate way at the surface. The lateral branches go off horizontally, or are a little directed upwards. The branches are quite short below where they begin, and also at the top they are most frequently shorter than in the middle. The upper end is of a peculiar structure, the branches here coalescing to a different number of longitudinal keels, the edges of which are set with a dense fringe of projecting spicules. This structure may be more or less marked, and seems also sometimes to be wanting, but when this is the case it is difficult to decide whether the sponge may not be damaged. The specimens in hand that are not broken off below are attached to pebbles; from the Kara Sea we have specimens attached to shells and tubes of Pectinaria hypcrborea. The largest specimen (from the Kara Sea) has a length of I20 mm ; the stalk is here very short, and its length cannot be given exactly, the projecting spicules of the stalk here, as in many of the specimens, passing by so imperceptible degrees into the lower short branches, that no distinct boundary can be observed. Below the stalk is fully i mm thick. Then we have individuals of decreasing sizes, the smallest, apparently entire specimen is full}- 20 mm high. By far the greatest number of the specimens are very slender and of equal thickness throughout their length; a few spe- cimens are somewhat more robust and a little thicker in the middle, so as to be slightly fusiform. The consistency is rather firm, but the sponge is flexible; the stalk is hard. The colour (in spirit) varies from white to light brown. The surface, with the exception of the stalk, must be said to be smooth, as spicules only project at the ends of the branches. The stalk, on the other hand, is very shaggy from rather close-set, projecting spicules which pass quite evenly into the lower short branches. The dermal membrane is without megascleres, and is distended by the skeleton of the branches; it is closely filled with chelae. I dare not decide anything as to pores and oscula. A few, roundish apertures are 64 PORIFER.A. II. .seen in the skin, most frequently of a size of about o-oc/ 11 " 1 ; they belong presumably to the incurrent system; the excurrent system opens possibly in the branches, which would then act as oscula. The skeleton is chiefly arranged as in A. bikamatifera. It consists of a spicula-axis, which is not compact, but formed by a number of fibres arranged in a circular way round the middle; between these fibres the short fibres or spicula-bundles that form the skeleton of the branches are inserted, so as to meet in the middle. The fibres of the branches may often be seen not to be solid, but their inner part is hollow, so that they do not pass to the middle as solid fibres, but some of their spicules are inserted in one place of the axis, some in another place. In the periphery of the axis no spicules are found here, as was the case in biliamatifcra, the dermal membrane is supported and distended only by the skeleton of the branches; at most a few scattered spicules are found. In the lower part of the stalk where spicules project all round, no circularly arranged fibres are found, but the spicules of the axis are seen in a transverse section to be more evenly distributed, or irregularly grouped, and the projecting spicules are inserted between them. In the axis a small amount of spongiu is found. Spicala: a. Megasclcra are styli; most frequently they are straight, more rarely quite slightly curved; only the shorter styli, and especially the quite short ones occurring down in the stalk, are always more highly curved. The long styli most frequently, but to an almost imperceptible degree, become thinner a little below the rounded end. The opposite end tapers gradually to a long point, which is sometimes, especially in the thicker spicules, more abruptly pointed at the extremity. There is no difference between the needles of the axis and those of the branches, but towards the base the needles of the axis get shorter, and here they occur of a particular form as short curved styli to which especially those needles belong that project and make the stalk shaggy. These shorter, curved styli, to be sure, occur here as a particular form, but they are connected with the other styli by a series of transitional forms. If all sizes are included the length varies from 1-5™™ quite down to o-238 m '"; if the lower part of the stalk is excluded, o'6 ,n,n may be given as about the lower limit, and the upper limit of the basal spicules may be put about at o-4 ,mn , but, as before mentioned, the two forms pass into each other. If all the forms are included the thickness is between o-oo7 mm and o-02i mm ; it is tolerably proportionate to the length, and with regard to the short curved styli it does not exceed 0-015"™. Some fine to quite fine developmental forms are seen. b. Microsclera ; these are anisochelas palmatse and forcipes. 1. The anisochelse are of the type of the subgenus and are constructed in quite the same way as those of the preceding species. Their length is o-oi4 mm , varying very little to both sides; in one large and robust specimen they reach a length of o-oi7 mm ; the breadth is o-oo7 mm . 2. Forcipes; these are longer and finer than in the preceding species. They are thickest above, and may here, when seen from the side, show a slight, tubercle-shaped swelling. They are of a characteristic form; from the curve the legs continue parallelly or in a slightly diverging manner, then follows a bend in such a manner, that the ends converge (PI. XI, fig. 6d) 1 ). The legs end in a small, distinct knob; they decrease in thickness outward, and in their outer part they are so fine, as to be only discerned with difficult)'. The length is rather constant, and was measured to 0-050 — o-056 mm . As mentioned, they are very fine, the thickness of the legs does not exceed o-ooio mm above, and towards the point they are much finer. *) If specimens are sometimes seen with their legs bent in other ways, this is, no doubt, only owing to the fact that they are under pressure in the preparation. PORIFERA. II. 65 The chelae are found in very great numbers, and especially the dermal membrane is closely filled with them; forcipes are few in number, and occur chiefly at the top of the sponge. Embryos. Also in this sponge embryos are found in most specimens and in very great numbers. They are situated in cavities in the tissue. The)- are very varying in size, from 0-05 — o-23 mm . The larger ones are provided with both megascleres and microscleres. The megascleres are styli which are straight or more or less curved. They reach a length of cri6 mm . According to the stage of development of the embryo they are of different thickness, from rather fine ones to ca. croo7 mm at the upper end. The megascleres seem to appear first, as in the smaller embryos with fine styli no chelae were seen. The styli are collected into a bundle reaching almost quite through the embryo, some of them have the point turned one way, some the other way. When the embryonic styli are somewhat curved, they remind very much of the curved styli occurring in the lower part of the stalk of the sponge, but they do not reach the size of these latter 1 ). The chelae of the embryos are here of the same size as those of the grown sponge, only in a few cases they seemed to be a trifle smaller. In the smallest embryos no spicules were found. Levinseu thinks that in this species a formation of buds takes place in the point of the lateral branches. I am inclined to think that the question is of embryos leaving the sponge through the lateral branches, which, as before mentioned, perhaps act as oscula. I have not seen embryos lying in the branches, but they are often seen lying at their base, and in some cases they were found hanging at the very point of the branches. This species, which by Levinsen I.e. has been established as a variety, is, besides by other characters, also by its spicules, as well megascleres as both forms of microscleres, separated from the preceding one in a constant and sure way. Levinsen's statement, that the styli are longer and finer than in the preceding species, is not quite correct; they are longer, to be sure, but at the same time they reach a greater thickness. Armauer Hansen's figures quoted above, I suppose to belong to this species. As mentioned under the preceding species I have been able to decide by an examination of a type-specimen that one of the specimens of Espcrclla Fristedtii mentioned by Lam be belongs to this species, viz. the specimen with longer and thicker styli and smaller chelae. Thus Lambe's species E. Fristedtii must be dropped. Locality: By the Ingolf Expedition the species has been taken on station 44, 6i° 42' Lat. N., 9 36' Long. W., depth 545 fathoms; station 143, 62° 58' Lat. N., 7 09' Long.W., depth 388 fathoms (bottom tempe- rature -t-o°4C); we have it further from the following localities: 6i° 30' Lat. N., 4 26' Long.W., depth 505 fathoms (bottom temperature -j- o°4 C.) (Wandel); 70 32' Lat. N., 8° 10' Long. W., depth 470 fathoms (the East Greenland Exp. 1890—91); 62 40' Lat. N., i° 56' Long. E., depth 365 fathoms (bottom temperature -=-o°3C); 6o° 09' Lat. N., 5 22' Long.W., depth 620 fathoms (bottom temperature -j-o°i5C.) (Ad. Jensen, the cruise of the «Michael Sars 1902). Nine specimens have been taken in all. The localities are situated east and west of the Faroe Islands, west of the Shetland Islands, between the Faroe Islands and Nor- way, and south of Jan Mayen. Geogr. disfr. The Kara Sea, depths 51 — 81 fathoms (Levinsen), the Baffin Bay, depth 130 fa- ■) As these sponges are most frequently highly filled with embryos, it will generally be the fact, that embryonic spi- cules are found in the spicula-preparatious, and by judging of the spiculatiou attention must be paid to this fact. The Injolf-Expedition VI. 2. q 66 PORIFERA. II. thorns (Lambe). Also this species seems to be a native of the cold bottom ; to be sure, a bottom temperature of 4°8 C. is stated for station 44; but in its immediate neighbourhood, on station 43, so low a positive temperature as o°5 C. is found. It is worthy of notice that in the three species of the subgenus Asbestopluma and the two Lycofodina-apecies now treated, which are in all principal respects of the same outer form, the skeleton of the axis is formed in a somewhat different way. In pennatula only few spicules are found in the middle of the axis, and also between the canals only narrow spicula-parts occur; outermost, on the other hand, there is a powerful spicula-layer, to which the firmness of the axis is especially owing. In bihamatifera a circle of powerful fibres is found, and outermost only a thin spicula-layer. In furcata the axial skeleton is divided into more or less narrow spicula-parts, and outermost is found a rather powerful spicula-layer. In cupressiformis we find a strong skeletal axis situated in the middle, the spicules of which may be more or less gathered into fibres, which are then connected by a network of not parallel spicules. In lycopodium, finally, there is a circle of separate fibres, and here no spicula- layer is found outermost. 6. A. hydra n. sp. PI. II, Figs. 18, 19. PL XI. Fig. 8 a— f. Formed like a tree with brandies issuing from the upper end of a stalk. The skeleton consists in the stalk of a spicula axis, in the upper end of which the fibres of the branches are inserted. Spicula: Megasclera subtylostyli, in the axis 077 — o-S""". in the branches 0-35 — o-6o'"'"; microsclera of one form, anisochehr palmatcr of the characteristic type 0-012— 0-014""". This small Lycopodina-sptcies is of an exceedingly beautiful and elegant form. It consists of a stalk ending in a swelling above, from which issues a number of thin, undivided branches. Below it is by an expanded basal part attached to a small stone, a lump of sand, or the like. The stalk is cylindric and straight. The sponge is of small size, the largest specimen is i2 mm high, and the greatest length of the branches is 4— 5 mm . The stalk is only ca. o-i5 ,nra thick, and the branches ca. 0'C>5 mm . The smallest specimen is 5 mm high. The branches may be of somewhat varying length, and in a few cases they are quite short or almost wanting. In the latter case the upper side of the swelling is densely shaggy from projecting spicules, which, as far as I have been able to decide, belong to the thinner form, occurring in the branches. The swelling, from which the branches issue, seems also to be always larger and more compact, when the branches are quite short or wanting, than when they are present in their full length; therefore I am also here inclined to think that the branches are able to contract. The consistency is firm, as the greater part of the sponge consists of spicules with com- paratively little soft tissue, but the sponge is flexible and elastic. The colour (in spirit) is white or slightly whitish yellow. The surface is smooth on the upper part of the stalk and the branches, only in the ends of the branches the spicules project. The lower part of the stalk and the basal expansion PORIFERA. II. 67 are shaggy from projecting spicules. On the stalk and the branches only a very thin layer of tissue is seen; on the thickened part between the bases of the branches, on the other hand, tliere is a thicker layer of tissue, which is bounded outwardly by a dermal membrane, supported by no particular skeleton, but provided only with microscleres. Pores and oscula were not seen. The skeleton. In the stalk the skeleton consists of needles closely united and parallel to the longitudinal axis. The spicula-axis formed in this way divides above into a number of more or less distinctly separated fibres bending a little outward, and between these fibres those of the branches are inserted. These latter fibres also consist of closely united, parallel spicules. As will be more par- ticularly mentioned below, the spicules of the stalk are thicker and more fusiform, those of the branches more slender and less fusiform. In the stalk a rather slight amount of very clear spongin is found. Spicnla: a. Megasclera are subtylostyli of two- forms, those of the stalk and those of the branches. The subtylostyli of the stalk are straight, rather thick, and highly fusiform, tapering much towards the head-end; the tapering may otherwise be somewhat varying. They have a head-swelling which is most frequently inconsiderable, and almost always placed a little below the end. The oppo- site end tapers from the middle evenly towards the point, but the end itself is somewhat more abruptly pointed, especially in the thicker ones. The length is rather varying, from 0-47 — o-8 mm , and the thickness from 0-017— o - 028 mm , the thickest ones being far from always the longest ones. The spicules of the branches are likewise straight, or very slightly curved, fusiform subtylostyli, but they are somewhat slenderer than those of the stalk, and so they are not so markedly fusiform as those. The swelling of the head-end is a little more pronounced, and is also here placed a little below the end. The opposite end is long and evenly tapering. Their length varies between 0-35 — o-6 mra , and the thickness varies proportionately between o-oo6— o-oi4 mra . As mentioned above the larger spicules form the skeleton of the stalk, and the smaller ones that of the branches, which is formed exclusively by these latter, but they may also be found in small number in the periphery of the stalk, and the spicules projecting in the lower part of the stalk are of this form. Thus the two forms of spicules have each of them a special place of occurrence, and they show also so much difference as to form, that they may generally be referred at once to their separate group. It is, however, scarcely to be supposed that they form two fundamentally different forms, as transitions are found between them, and these transitional forms occur exactly at the place where the stalk and the branches pass into each other. Here, in the thick- ened part, from which the branches issue, transitional forms are found that may be referred to one form as well as to the other. The basal expansion is formed by both kinds of spicules, the prominent ones seem chiefly to belong to the smaller form; but here again the two forms are not sharply separated, but transitional forms occur, b. Microsclera; these are of one kind only, anisochelse ■palmatEe of the Lycopodi/m-type; they have a form quite similar to that of the chelae in the two preceding species, but they are a little smaller, the length is 0-012— o-oi4 m,n , most frequently, however, the latter length; the breadth is o-oo5 mm . The chelae, as usual, occur throughout the tissue, but are especially numerous in the dermal membrane. Locality: Of this small, interesting, and beautiful species, which is easily recognizable by its outer form alone, the Ingolf-Expedition has obtained fifteen specimens in all; most of them were not found till after the return of the Expedition, when they were discovered in the bottom specimens 9* 68 PORIFERA. II. growing on pebbles and particles of gravel. Station 113, 69 31' Lat. N., 7 06' Long. W., depth 1309 fathoms (bottom temperature -r- i°oC), thirteen specimens; station 119, 67 53' Lat. N., io° 19' Long. W., depth 1010 fathoms (bottom temperature -j-i°oC.), two specimens. Thns also this species is a native of the cold bottom, and it is only known from great depths. Both the stations are situated between Iceland and Jan Mayen. Cotylina n. subg. Formed like a calyx (or head) on a rather long stalk. The skeleton consists in the stalk of a spicula-axis, in the calyx-wall of more irregular arranged spicules. Spicula: Megasclera styli or sub- tylostyli, often divided into several forms occurring in fixed places in the sponge; microsclera : the cha- racteristic anisochehr palmatce have the aire of the larger end reaching to about the middle of the shaft, the smaller end is somewhat longer than in Lycopodina, of a. similar structure, but elliptical in a trans- verse section: to the chela' may be added forcipes. 7. A. infundibulum Levins. PI. II, Figs. 20—21. PI. XI, Fig. 9 a — m. 1874. Esperia cupressiformis Carter, partim, specimen in interclusione commemoratum, Ann. Mag. Nat. Hist. Ser. 4 , XIV, 215, PI. XIV, fig. 19 a, b. 1885. Esperia bihamatifera Armauer Hansen, partim, the Norwegian North-Atlantic Exp. XIII, Spon- giadse, PI. Ill, fig. 6. 1887. Esperclla infundibulum Levinsen, Dijmphna Togtets zool.-bot. Udbytte 366, 19, Tab. XXIX, Fig. 14, Tab. XXXI, Fig. 17—19. Formed like a calyx on a long stalk. The skeleton consists in the stalk of a spicula-axis, in the calyx-wall of less regularly arranged spicules; on the outside of the calyx spicules project. Spicula: Megasclera of three forms, styli or subtylostyli in the axis and the calyx-wall o-ij — 0'8j mm , styli zoith a very long, fine point, projecting on the outside of the calyx 0-44 — o-6""", subtylostyli in the refolded edge of the, calyx 0-149 — 0-22""": microsclera of two forms, the characteristic anisochehr palmata- o-oiS — 0-02^""". forcipes o-oy^""' 1 . This species is formed like a calyx placed on a long, thin stalk. The calyx may be somewhat differently shaped; most frequently it has a regular form as a short funnel and with a wide round opening, but sometimes it is highly compressed, so that the two sides are closely joined, and the opening becomes a narrow slit. Of the specimens from the Ingolf-Expedition one is torn off, the other is attached to some sponge-spicules. From the Kara Sea we have it attached to tubes of Pecti- •uaria hyperborca. The largest specimen in hand (from the Kara Sea) is 50"™ high, of which the stalk makes 42 mr "; the compressed calyx is ca. io mm in diameter. The stalk is very thin, 0-5— i mro , a little thicker below than above. The smallest specimen is i4 mm high, and has a very small calyx of a dia- meter of only i-5 mm . The edge of the calyx looks as if it was thickened, but this is owing to the fact that the edge is refolded, and the fold fits closely to the inside. The calyx is of a rather soft con- PORIFERA. II. 69 sistency, the stalk firm, but flexible. The colour (in spirit) is a dirty eream-colour. The surface, both of the stalk and of the outside of the calyx, is shaggy from projecting spicules. There is a thin dermal membrane, which on the outside of the calyx is pierced by the projecting spicules. Pores and oscida have not been seen with certainty; on the outside were seen scattered openings of different sizes, and in one specimen there were a few openings in the bottom of the calyx; but in both cases the question is possibly only of damagings of the soft tissue. The skeleton. The skeleton of the stalk consists of an axis of closely united needles parallel to each other, between which are interwoven other needles which jut out horizontally. Above the axis is divided more or less distinctly into fibres that pass into the skeleton of the calyx. In the calyx-wall the skeleton consists of needles which are not united into fibres, and a great part of which are placed chiefly in the longitudinal direction; they are not, however, parallel to each other, but inter- cross irregularly, and some are also found placed in other directions. Between these needles spicules and spicula-bundles are inserted on the outside, projecting through the surface and directed somewhat upwards; the inside of the calyx, on the other hand, is smooth without projecting spicules. In the upper part of the calyx-wall the spicules are closely packed and parallel to each other; in the refolded edge spicules are found of a special size, as will be more particularly mentioned below ; moreover, this edge is highly filled with chelse. Spongin is found, at all events in the stalk. Spicula •■: a. Megasclera. These are styli or subtylostyli; they fall under several forms which also occur in different places of the sponge, but on account of the slight material, I have had some difficulty in examining this fact. The skeleton of the stalk and the greater part of that of the calyx consists of long, slender styli, which have sometimes a small head-swelling. They are fusiform, taper- ing a little towards the head-end, and they have an evenly tapering, middle-long point. Downward in the stalk they become shorter and also somewhat curved, and the spicules that are horizontally interwoven in the stalk and projecting are all short and curved. In most individuals these projecting, shorter, and a little curved needles deviate further by having a more or less distinct head, so that they become tylostyli. Taken as a whole these styli vary from ca. 0-17— o-83 mm , but in the calyx and the upper part of the stalk they do not generally go below ca. o-3 mm ; the thickness is 0-0057 — o-oii mra . Besides these styli, which form, accordingly, the principal part of the skeleton, still two other forms are found; the first of these are very slender styli, showing sometimes an almost imperceptible head- swelling; they are considerably finer than the preceding ones, and they have a very long, fine point, almost always with an even curve; their length is between 0-44— o-6 mm ; in their lower part they are slightly fusiform, and their thickness in the thickest part is at most o-oo7 m "'. These spicules are found outermost in the calyx-wall and project from it; they seem mostly, but not exclusively, to form the projecting spicules. The third form of megascleres are short, straight tylostyli or subtylostyli; the head is tolerably well marked and placed a little below the rounded end, the point is short. Their length is 0-149 — o-22 mm , and the thickness is o-oo6 mm . These spicules are found in the refolded edge, and they form the spiculation of this edge. These three forms of spicules, of which only the first- mentioned form is very varying, while the two other forms are rather constant as to form and size, do not appear to be connected by transitional forms, b. Microsclera. These are anisoehela; palmatae and forcipes. 1. The anisochelse are Asbesloflluma-chelse of a structure characteristic of the sub- 7Q PORIFERA. II. genus. The alse of the larger end do not reach so far down along the shaft as in the chelae of the two other subgenera, only to about the middle of the shaft; they bend somewhat forward towards the tooth; together they form almost a triangle, and the}' go in to the shaft with a somewhat indented lower edge. The tooth is elliptical, of about the same length as the alse, but much narrower; it has a long, narrow, downward pointed tuberculum. It is very difficult to get a clear view of the structure of the smaller end on account of the fineness and transparency of the parts. The structure of this end may best be compared with that in A. cHpressiformis, but it is comparatively larger, and the parts are of a somewhat different form. When the chela is viewed from the side, two long, narrow, ridge- shaped bodies that are parallel to each other and run close together are seen at the lower end of the axis. If the chela is turned with the lower end directly towards the beholder, it is seen that the question, as usual, is of alse and tooth, but the optical transverse section does not, as in cupressiformis, form a circle, but on the contrary an ellipsis placed transversely, alse and tooth being nearer to each other and therefore less refolded on the side, where they are separated by a quite narrow slit (PI. XI, fig. 9 h). When the chela is viewed from the front under sufficient magnifying powers, it is seen that the alse form together an almost quadrangular plate, the upper corners are somewhat drawn out, and there is a round incision about to the middle of the ala, which gives to the plate formed by the alse a shield-shaped appearance. The upper edges of the alse continue inward to about the median line of the shaft and form two projections separated from the outdrawu corners by a curve. The tooth is of a similar form as the plate formed by the alse, the upper edge has three teeth, and the upper half of the lateral edges is cut off obliquely. Thus, as in cuprcssiformis, only the lower half of the lateral edges of the alse and tooth is refolded and meets on the side. The drawn-out upper corners of the alse and the mentioned middle projections are directed forward, and when the chela is viewed from the side, they form the forward directed upper part of the hindmost of the two parallel ridges. The tooth has an oblong, somewhat club-shaped tuberculum which is broadest upward. The chela varies somewhat in size, not so much in one individual, but rather considerably in different individuals. Together with the variation as to size we find some variation as to form, as the dimensions of the different parts of the chela may change somewhat. Especially in the smaller chelse the smaller end is comparatively longer and the middle part of the shaft a little shorter. The upper corners of the alse are often more drawn out and together with the middle projections directed more forward. The whole smaller end is at the same time more narrow, and the larger chelse are upon the whole com- paratively more robust than the smaller ones. The chelse occurring in the embryos show new differ- ences, the larger end and especially the tooth being longer, so that the two ends of the chela almost meet. The length of the chelae varies from o-oi8— o-027 mmI ), the greatest breadth varies proportionately from o-oio— o-oi4 mm , and the thickness of the shaft from ca. crooi— o-oo4 mm . Developmental forms of the chela are found rather abundantly, in all stages, from quite fine ones to the fully developed ones. 2. Forcipes; these seem always to have the form figured by Levinsen I.e., with one leg crossing the other; they are a little thickened above in the curve, the legs are exceedingly fine, and end in a little knob. The length is about o-ojs" 1 ™, and the thickness of the legs in the middle is less than t) When in one individual both large cheke and quite small ones are found, and when chelse are found considerably smaller than the given measures, this is owing to the fact that these chelae belong to the embryos; see below under Embryos. PORIFERA. II. 71 o-ooi mm . The chelae occur in large quantities, especially in the skin and also clown on the stalk; they are found in enormous numbers in the refolded edge the spiculation of which they form together with the mentioned short tylostyli. Forcipes are very few 7 . Embryos. In most specimens of this sponge embryos were found; they are situated in the calyx-wall, rather close-lying, and in rather large numbers. They are globular, of somewhat different size up to o-i8 mm in diameter. Their spiculation is somewhat interesting. They have both megasclera and microsclera; the microsclera are chelse of the same form as in the grown ones, but they are smaller, they were thus measured to o - oi4 mm . That some difference is also seen in the dimensions of the single parts has already been mentioned under the chelse. The megasclera show no likeness at all with those of the grown sponge; they are more or less irregularly, often highly curved, and they may be of different forms as strongyla, styli, or oxea, and they have swellings in different places; most frequently they are strongyla. In the largest of the embryos they were measured of a length of about o-i m,n and a thickness of 0-007 — o-oo8 mm , but in the smaller embryos they are considerably finer. In the examined embryos they were only present in small numbers, about ten needles in each embryo. Remarks: After Carter's mentioning and figure I.e., there can scarcely be any doubt that the form mentioned there in the parenthesis is infundibulum\ in the specimen before him the calyx must then have been in a compressed state. Also Armauer Hansen's figures cited above are surely infundibulum. As I have had Levinsen's type specimens from the Kara Sea for examination, I have been able to determine the species with certainty. Levinsen, by his mentioning of the chelae, states that in a specimen of cuprcssiformis he has found the same chela as that occurring in infundi- bulum, only, however, to a number of five; therefore he thinks that this chela is identical with the one figured by Vosmaer (Niederl. Arch, fiir Zool. Suppl. Baud I, PI. I, figs. 109— no) as belonging to the species enumerated as Cladorhiza bihamatifcra, as he supposes cuprcssiformis and bihamatifcra to be one species. As will have been seen before under bihamatifcra, this, however, is not the fact; Vos- maer's species is pcnuatula, and the large chela in this species as well as in bihamatifcra is of a quite different type, and the five chelae found by Levinsen in cuprcssiformis must have been extra- neous bodies; extraneous microsclera are frequently found, especially microsclera from sponges growing in the same place. With regard to the description of the smaller part of the chela Levinsen has not interpreted the form of this part correctly. His figures are good, and show the occurring variations in an excellent manner; but by the magnifying powers he has used, he has not been able to get a view of the fact that the smaller end consists in the common way of alas and tooth, but interprets this end as forming a cup, at the bottom of which the tuberculum is placed. Locality: Station 116, 70° 05' Lat N., 8° 26' Long. W., depth 371 fathoms (bottom temperature -=-o°4C); station 126, 67° 19' Lat. N., 15° 52' Long. W., depth 293 fathoms (bottom temperature -=-o°5C); station 143, 62 58' Lat. N., 7 09' Long.W., depth 388 fathoms (bottom temperature -=- o°4 C). These three stations are situated north of the Faroe Islands, north of Iceland, and south of Jan Mayen, and they are all in the cold area. Geogr. distr. With regard to the specimens of the Norwegian North Atlantic Expedition, the particular locality is not known; Carter's specimen was taken by the < Porcupine ^ south of the 72 I'ORIFKRA. II. Faroe Islands, depths 363 fathoms and bottom temperature -f- o = 3 C. Levinsen's specimens are from the Kara Sea, depths 50 — 70 fathoms, the bottom temperature is also here negative. From these facts it is seen that the species is a native of a bottom with negative temperature. 8. A. comata n. sp. PI. II, Figs. 22—23. P1 - XI1 ' Fi g- l a ~ f - Formed as a compressed calyx on a stalk; the upper end of the calyx with a fringe of exceedingly fine spicules. The skeleton consists in the stalk of a spicnla axis, in the calyx-wall of needles, partly placed in the longitudinal direction; from stalk and calyx spicules project. Spicula: Megasclera of four forms, stv/i in the axis 0-44 — o-j/""", subtylostyli in the calyx-wall 0-238 — 0-476""", subtylostyli in the refolded calyx-edge 0-149 — 0-23""". and styli with a long, curved, very fine point, projecting from the stalk and the calyx and forming the upper fringe 0-7 — 1-4""". between them pearl-st ring-formed styli ; microsclera of one form, anisoclielce palmatie of the characteristic type 0-017 — 0-0/9""". Of this species we have only one specimen, and the fact of this species being of a very slight size has somewhat hindered the examination. As to the exterior it is somewhat similar to iufuudi- bulum, and is formed as a calyx on a thin stalk; the calyx is highly compressed, and consequently flat. From the stalk and the calyx long, hair-like needles project and form round the edge of the calyx a fringe which is, however, little conspicuous to the naked eye. The stalk is below for some way attached to a spouge-spicule, which accordingly serves as a substratum for the sponge. The total height of the sponge is io mm , of which the stalk is fully 7"™. The breadth of the calyx is 2 mm , and the thickness of the stalk only crio mm The colour (in spirit) is whitish The surface, as before men- tioned, is shaggy from long, hair-like spicules. With regard to dermal membrane, pores and oscula I can say nothing. The skeleton. In the stalk the skeleton consists of an axis of closely united parallel spicules. From this axis fine, long-pointed spicules issue; with their head-end they are interwoven between the spicides of the axis, or otherwise attached to the axis, and the}' are very projecting; in the lower part of the stalk they project almost horizontally, but they become the more upwardly directed, the farther up the stalk we go. The stalk passes gradually into the calyx; in the lower part of the calyx- wall the spicules are not arranged in any observable order; some are lying in the longitudinal direc- tion, but otherwise they are lying in all directions parallel to that in which the wall extends. In the upper half of the calyx-wall the spicules are arranged in such a manner as to be lying chiefly or exclusively in the longitudinal direction parallel to each other, and from here issue the spicules that form the mentioned fringe along the edge of the calyx. In the upper edge of the calyx, which is also refolded in this species, shorter spicules of a particular form are found. In the stalk spougiu was observed. Spicula: Megasclera; these are styli or subtylostyli, and they occur in several forms. The axis of the stalk is formed by styli which are straight or most frequently slightly curved; they are fusiform, tapering somewhat towards the head-end, the opposite end grows evenly thinner to a long point. Their size seems to be rather constant, their length was measured to 0-44— cr5i mm , the thickness is PORIFERA. II. o-on — o-oi2 mm . The needles chiefly forming the skeleton of the calyx-wall are of a somewhat different form; they are straight or, more rarely, a little curved subtylostyli with a rather distinct, but small head-swelling, placed a little below the end; they are only a little thicker in the middle than at the upper end; the point is even, but not long. The length was measured from ca. 0-238 — o-475 mm , an< l the thickness is 0-007 — o-oo8 mm . Besides these two forms short subtylostyli occur abundantlv in the mentioned refolded edge; they are of quite the same form as the preceding ones, the length is from o-i49 mm to about o-23 mm , and the thickness is 0-005— o-0O7 mm ; as mentioned, they occur onlv in the refolded edge, but their size, which passes into the size of the other subtylostyli, seems to make it doubtful whether these two kinds of subtylostyli are really different. The fourth form of megasclera is the one most characteristic of the species; it is the long spicules projecting from stalk and calyx and forming the crown at the top. They are long, thin styli running out into a very long and very fine point. They are almost always evenly curved in the outer part; sometimes the curving is a little irregular. Their length is very varying, it may be given to between 0-7 and r4 mmi ). The thickness at the head-end is ca. o-oo5 mm . Down at the base of the stalk they seem to be shorter, and these short needles often have a head-swelling. Among the projecting needles some are found of a very charac- teristic appearance; in a shorter or longer portion of their outer part they have a series of ring-like swellings, so that they get an appearance like a string of pearls; together with this feature they have often a somewhat shorter point, and their length may then go down to o-65 mm , and they are likewise often somewhat more robust, of a thickness of up to o-oi mm . As these needles have otherwise the same form and occurrence as the other projecting ones, they are scarcely anything else than a variation of the same type. The needles projecting from the axis are partly interwoven between the parallel spicules of the axis, partly they are, a great deal of them, attached to its outside, b. Aficro- sclera ; these are only of one kind, anisochelse palmata;, and they are of quite the same structure as the cheke in infomdibulum ; their length is 0-017 — o-oio, mm aud the breadth o-oo8 mm . They are present in great numbers and occur especially abundantly in the refolded edge of the calyx. This species seems to be closely allied to A. infundibulum, both on account of the outer form and of the projecting, long pointed styli, but it differs from it among other things by other sizes of the different forms of needles, and by the occurrence of peculiar, pearl-striug-shaped needles. These spicules recall to some degree those in Meliiderma stipitata described' and figured by Ridley and Dendy, but these latter are much shorter and shorter pointed. Locality: Station 78, 6o° 37' L,at. N., 27 52' Long. W., depth 799 fathoms; the station is situated on the eastern slope of the Reykjanes-ridge. The genus Asbestopluma forms a well characterized genus, the species of which are also char- acteristic in their exterior by being all of erect and symmetrical form, aud also the skeletal structure shows great conformity. Outside this genus a similar form occurs in Cladorhiza, and among the ') Exact limits for the length of these spicules cannot be given, as the outermost point is wanting in almost all of them. The Ingolf-Expedition. VI. 2. IO 74 TORIFERA. II. Esperiopsis-spedes one species is found, E. symmetrica R. and D. (Chall. Report. XX, 77, PI. XXVI, figs. 4, 4a), which shows, in its outer form and skeletal structure, very great conformity to several of the Asbestoplu wa-species. A conspicuous peculiarity common to the Asbestopl// ma-species is the fact, that embryos are so often found. Also in the mentioned Esperiopsis-species embrvos were found occurring in the same way as in the Asbestopl// ma-species. The embryos, otherwise, show some difference in the different species with regard to the spicules occurring in them. Embryos were found in the species pennatula, furcata, cupressiforn/is, lycopodium, and iiifundibuhtm. The difference in their speculation may be seen in the following table: Size of the • , .. embryo Spiculation pennatula 0'5 — I mm ;No megasclera, only sigmata and the small chela. Sigmata seem to appear first. furcata <-,.-, mm Megasclera small snbtylostyli of an average length of o-2o8mm; microsclera sigmata and the small chela, both a little larger than in the grown sponge. cupressifor/l/is CO5 — Cr27 m,n Megasclera small subtvlostyli, often irregularly formed, and styli, strongyla, etc., arranged in a bundle. The length up to o-i2 mm ; microsclera chelae a little smaller than in the grown sponge. Ivcopodiu/U O'OS — Cr23 mm ! Megasclera small, straight or curved, styli arranged in a bundle, the length up to o-i6 mm ; microsclera chelae of the same size as in the grown sponge. Megasclera appear first. infundibulum up to C)'l8 mm Megasclera quite irregular styli, strongyla or oxea, the length up to crimm. Microsclera chelae a little smaller than in the grown sponge. Among the earlier described Asbestoplu ma-species embryos are mentioned in two, viz. in biseri- alis R. and D., in which, as in pennatula and furcata, they are found in the axis; the only thing said of them is that they have numerous spicules; further in vcrsatilis Tops., of which it is stated that they have of megasclera oxea and strongyla, and of microsclera cheke 1 ). Top sent, who, in 1901 (Resultats du Voy. du S. Y. Belgica, 23), takes up and diagnosticates the genus Asbcstopluma, enumerates at the same time the six species which, in his opinion, belong to it, viz. cuprcssiformis Cart., bihamatifera Cart, pennatula Schmidt, biserialis R. and D., Nordenskioldii Frstdt, and the new-established species Belgica. Of these species Nordenskioldii, as above mentioned, is syno- nymous with pennatula. Some more species have been described, however, which Tops en t has not noticed, but which belong here, viz. besides the already described infundibulum Levins., the species vcrsatilis, established by Topsent himself in 1892 (Resultats des Campagn. scient. du Prince de Monaco, Fasc. II, 100, PI. VI, fig. 5, PI. X, fig. 9), and by him referred to the genus Forcepia, as well as the Esperella occidentalis established in 1893 by Lam be (Transact, of the Roy. Soc. of Canada XI, Sect. IV, 28, PI. II, figs. 6, 6 a — e), and the E. mi/iuta established by Lambe in 1900 (ibid. Ser. 2, VI, Sect. IV, 23, PI. I, figs. 3, 3 a— c). Thus besides the eight species taken by the Ingolf, the following ones belong to this genus: biserialis R. and D., Belgica Tops., occidentalis Lambe, vcrsatilis Tops, and ///inula Lambe. ') According to the statement of Topsent, it was to be supposed that the embryos had the microsclera occurring in the species, viz. chelae and forcipes; but to judge from the figure they have only cheke, and this, I suppose, is the cor- rect tiring. PORIFERA. II. 75 A. biserialis R. and D. is a peimiform species provided with axial styli, reaching a length of 2""", and subtylostyli in the branches 044""" long. Of microsclera are found palmate anisochelse o-oi2 mm long, and sigmata cro25 mm long. Unfortunately no anisochelse are figured, but they may certainly be taken to belong to the form peculiar to the subgenus Asbestopluma. Its combination of spicules places it nearest to Belgica, as sigmata and only one form of chelse are found in it, but the arrangement of the lateral branches separates the two species sharply. Ridley and D e n d y do not mention any stalk-coating, but there is some reason for believing that such a one is found; it may either have been overlooked or wanting in their two specimens both of which were broken off below. A.Belgica Tops., as to its exterior, recalls bihamatifera\ accordingly it has branches issuing all round, but the branches are arranged in groups of circles, and the groups are separated by naked intervals. The number of circles in the group varies from five to ten, but the number of branches in the circle is always six, and the branches are placed just over each other. The spiculation shows of megasclera axial styli 14™™ long, with a little tapering upper end, and in the branches tylostyli ca. o-8 mm long, further in the stalk-eoating curved, finely spinulous tylostrongyla of an average length of 0-2""". The microsclera are anisochelse o-oi2 mm long and sigmata o - 033 mm long. Topsent's figure shows that the anisoehelae are of the type characteristic of the subgenus Asbestopluma. This species, which is so interesting with regard to its exterior, is by the spicula-combinatiou sharply separated from the other species, with the exception of biserialis, to which in this respect it is closely allied. A. occidentalis Lambe is a species closely allied to citprcssiformis and lycopodiiaii, but separated from these not only by the sizes of the spicules, but also by the skeletal structure, as it has, besides a hollow middle axis of spicules, also an outer circle of spicula-fibres, while lycopodium, to which it is most closely allied, has no such outer circle. Megasclera are styli growing to a length of r39 m,n ; those found in the part of the branches inserted in the axis are given to a length of 0-41 — o - 68 mm ; microsclera are anisochelse croi3 mm long, and forcipes o-032 mm long. From Lambe's figure of the chela it cannot be decided with certainty that it is of the form typical of the subgenus Lycopod/i/a, but this will certainly prove to be the fact. To judge from the figure, forcipes have a particular form. A. versa filis Tops. Top sent referred this species to the genus Forcepia, partly on account of the fact that forcipes are found in it, and partly because he found embryos, in which he found diactinal spicules which he took to be the dermal spicules of the species, which did not later develop further, so that the}" were wanting in the grown sponge. The species is, however, surely an Asbestopluma of the subgenus Cotylina, and seems to be closely allied to infundibulum, with which species it shows some conformity both in its exterior and its spiculation. That it is an Asbeslopluina is seen from its chelae, which, as far as can be seen from Topsent's figure, seem to belong to the Cotyli>ia-type, and as forcipes are also found in this genus, their occurring here cannot solely justify the referring to Forcepia. Also its anisochelse tell against referring it to this genus, as all the other Forcepia- species have isocheke. With regard, finally, to the embryonic spicules, I do not think that the forms figured by Top sent recall the dermal spicules of the Myxillina. Quite similar spicules, as will have been seen, are found in the embryos of infundibulum, they are only more irregular, and also monactinal spicules are found between them. To be sure, the question is here of embryonic spicules -6 PORIFERA. II. that cannot be interpreted as special dermal spicules. The species has of megasclera stvli o-58 mm long, of microsclera anisochelse oo27' nm long, and forcipes o - 076 mm long 1 ). A. minuta Lambe might, as to its exterior, remind of infundibulum, but its spiculation is differ- ent. According to Lambe the megasclera are of two kinds, styli or subtylostyli 0-327 — o-543 mm long and o - oo6 — croo8 mm thick which form the principal part of the skeleton, and small tylostyli 0-196 — o-294 mm long and 0-005 — o-oo6 mm thick which project from the surface. The microsclera are anisochelse o - oi8 — 0-019™™ long, which, to judge from the figure, may be said with certainty to belong to the Cotylma-type. The genus As b estop luma, consequently, is chiefly characterized by its erect symmetrical form with the skeletal structure contingent npon this form, and by the occurrence of a small chela of peculiar type. As will have been seen in the preceding, it is, however, with regard to both these features, divided into three groups, and to this division contributes further the occurrence in one of these groups of sigmata and of a stalk-coating with special spicules. The subgenus Asbestopluma s. str., formed for the first of these three groups, is accordingly characterized as to its form by distinct, often rather long, well separated lateral branches, by a small chela, the larger alse of which reach far down towards the smaller end, which latter is narrow, and by the occurrence of sigmata and of a stalk- coating with a spiculation of finely spinulous tylostyli or tylostrougyla. On the other hand, the occur- rence of the large chela cannot be used, as this chela is wanting in two of the species. The second subgenus, Lycopodiiia, is characterized by its often shorter, sometimes less well separated branches, which also sometimes all issue from the top of the stalk, and by a small chela, the larger alee of which pass quite down to the opposite end of the chela, which end is broad and of a peculiar form. Sigmata and stalk-coating are not found. The occurrence of forcipes cannot be used, as these spicules partly are wanting in one species, and partly may be found in the third subgenus. This third sub- genus, Cotylma, is well characterized by its form, which is as a calyx (or a head) on a stalk; it has a small chela, the larger alse of which pass to about the middle of the shaft, the smaller end of the chela is constructed about as in the preceding subgenus, showing, however, characteristic differences, and a transverse section of it shows an elliptic contour. Sigmata and stalk-coating are not found, but forcipes occur in two of the species. Thus the two first subgenera are especially separated by the form of the chela, and by having or wanting sigmata and stalk-coating, the two last genera by the form of the chela and by the outer form of the sponge. Whether the peculiar, long pointed, pro- jecting spicules occurring in two of the described species of the subgenus Cotylina may possibly prove to be characteristic of the genus, cannot yet be decided. According to the account rendered in the preceding of the species that have not been fully- treated here, all the known Asbestoplin/ia-species may, as far as the fact can be decided from the lite- rature, be grouped in the following way in the established three subgenera: ') In Topsent's work from 1904, which I have received later, the author himself draws the attention to the fact that versatilis is to be referred here. I'ORIFKRA. II. 77 Asbestopluma s. str. pennatula O. S. biserialis R. and D. bilianiatifcra Cart. Bclgica Tops. /areata mihi. Lycopodina n. cuprcssiformis Cart. occidentalis Lambe lycopodium Levins. hydra mihi. Cotylina n. infundibulum Levins. comata mihi versatilis Tops. minuta Lambe. A systematic survey of all Asbestopluma-s-pecies may be given as follows: a. Sigmata are found; stalk-coating also (biserialis?): b. Two forms of eh else; besides the Asbestoplu wff-chela a larger chela of a different type: c. The lateral branches arranged biserially ; the spicules of the stalk-coating tylostrongyla pennahda O. S. ex. The lateral branches arranged pluriserially: d. The spicules of the stalk-coating tylostyli bihamatifera Cart d.d. The spicules of the stalk-coating tylostrongyla; the lateral branches very small furcata n. sp. b.b. Only one form of chelae: e. The lateral branches arranged pluriserially Bclgica Tops. c.c. The lateral branches arranged biserially biserialis R. and D. a.a. No sigmata; no stalk-coating: b. More or less marked lateral branches, or the branches all issuing from the top of the stalk. (Sometimes leaf-shaped without lateral branches): c. Forcipes are found; the branches are lateral: d. The fibres of the lateral branches do not go to the middle of the axis, chelae 0-023 — o-o25 mm , forcipes 0-038 — o-048 mm cuprcssiformis Cart. d.d. The fibres of the lateral branches are going to the middle of the axis: e. No spicula-fibres outside the axis; chelae 0-014 — o-oi7 mm , forcipes 0-050— o-o56 mm lycopodium Levins. ex. Spicula-fibres outside the axis; chelae o-oi3 mm , forcipes o - 032 mm occidentalis Lambe. c.c. No forcipes; the branches issuing from the top of the stalk; chelae o-oi2— o-oi4 mm hydra n. sp. 78 POR1FERA. II. b.b. Formed as an open or compressed calyx (or head) on a stalk: c. Forcipes are found: d. Calyx-shaped; several forms of megasclera, among which project- ing, long and finely pointed styli; chelse o - oi8 — o-027 mm , forcipes o - 075 mm infundibulum Levins. d.d. Not. calyx-shaped; only one form of megasclera; chelse o - 027 mm , forcipes o-076 mm versa t 'His Tops. ce. No forcipes: d. A fringe of spicules round the edge of the calyx; projecting spi- cules very long and fine styli, some of them pearl-string-shaped; chelse 0-017 — o-oio, mni comata n. sp. d.d. No fringe of spicules; projecting spicules short subtylostyli; chelae croiS— o - oi9 m "' minuta Lambe. Cladorhiza M. Sars. Erect sponges of definite form; branched in different ways or unbranched; often consisting of a middle axis sending off brandies to two sides or all round, more or less regularly, or branched from the base. Below the axis most frequently divides into a more or less richly branched root. The middle axis and the branches carry short brauchlets issuing all round and close-set. or these brauchlets are gathered at the top as a circle or a head, and then they are considerably longer. The skeleton is closely dependent on the form : it consists in axes and branches of a powerful, polysplenia?' fibre, often of great thickness: in this fibre are inserted the fibres supporting the brauchlets. In the axial fibres spougin is found. Spicula: megasclera are oftcuest styli. sometimes oxea; subtylostyli may occur; microsclcra : the charac- teristic microsclera are anisancora unguifera with three to five teeth in either end, sometimes up to nine teeth in the larger end; the an cone may be found alone or together with sigmata of one or two forms. With regard to the external form, as I have described it in the diagnosis, I shall remark that I entirely follow the opinion put forth by Top sent (Sur l'orientation des Crinorhiza, Compt. Rend. Acad, des Sc. 1902), and accordingly I am of opinion that Ridley and Dendy in Challeng. Report have turned their C. longipiuua. similis, and iuversa. as also their Axoniderma mirabile and Chondro- cladia crinita upside down. There can scarcely be any doubt that what they have had before them is nothing but torn off upper parts of sponges. The Cladorhiza-species seem, according to their form, to fall under two groups; one consists of slender, unbranched or, most frequently, branched forms the axes and branches of which carry every- where short branchlets; the other group consists of forms with an unbranched stalk or axis carrying above branches gathered in a circle or a head. These branches reach a considerably greater length than the branchlets of the other group, but they are, however, surely to be regarded as formations of the same kind, and do not correspond to the branchings of the axis. The fact is that the branches PORIFKRA. II. 79 of C. morula must be supposed to completely correspond to the branches in longipinna, similis, and inversa, and the figure of the skeletal structure in morula (I.e. 91) shows that the fibres of the branches are inserted in the same way as those of the branchlets of the species of the other group. The same fact is otherwise shown by the figure of the skeleton in Axoniderma mirabilr (1. c. 97). The branchlets in the C/adorhiza-species must be regarded as corresponding to what I have called the lateral branches in the Asbcsfopl/uua-species, as they are inserted in the axis in a quite similar way. Also in the genus Asbcstopluma, subgenus Lycopodiua, a species is found, A. hydra, which, instead of having lateral branches along the axis, has the branches collected at the top. 1. C. abyssicola M. Sars. PI. XII, Fig. 2 a— f. 1872. Cladorhiza abyssicola M. Sars, On some remarkable forms of animal life I (by G. O. Sars), 65, PI. VI, figs. 16-34. 1875. Cladorhiza abyssicola O. Schmidt, Jahresber. d. Comm. zur wissenschaftl. Unters. der deutsch. Meere in Kiel fur 1872 — 73, 119, Taf. I, Fig. 13. 1878. Cladorhiza abyssicola v. Marenzeller, Coelent. etc. d. osterreich-ungar. Nordpol-Fxp., Denkschrift. d. Kais. Akad. d. Wisseuschaft. Math. Nat. CI. XXXV, 371. 1896. Cladorhiza abyssicola Lambe, Proc. of the Roy. Soc. of Canada, Ser. 2, II, Sect. IV, 188, PI. I, figs. 8, 8 a — e. Slender, unbranched (young specimens), or with rather long brandies issuing from a central axis; below a richly branched roof. The skeleton arranged in the way characteristic of the genus. Spi- cula: Megasclera sfyli o-jp — o/j""": microselera of three forms, anisancorce tinguifcrcc with five teeth 0'02i — o-ojy"", sigmata of two forms, large ones o-o'/S — owo""", small ones with compressed end parts 0-040 — 0-042""". Of this species I have had only a slight material, and I therefore am only able to add little new to the very good and exhaustive description given by Sars. Of the specimens in hand the largest ones agree, as to their external form, with the description of Sars. They consist of a stalk, divided below into a great number of branches or fibres, so that a richly branched root is formed; to this root some bottom-material is still attached, among other things tubes of Rhabdammiua. The stalk is straight and from it go off lateral branches issuing at about right angles, only directed a little upwards. The lateral branches may be of different lengths, but generally they are longest below. The distance between them is different. The branches may be directed to different sides, but upon the whole a certain bilaterality is prevailing. Besides the branched specimens we have a couple of smaller ones consisting only of a central stem without branches, but otherwise of the same structure. From the stalk and branches branchlets or filiform appendages issue everywhere and on all sides. They are thin, thickest at the base, and tapering a little outward; they may be of somewhat varying length, but reach at most a length of ca. 5 mm . The branchlets are directed upwards in a somewhat arcuate way. At the point of the stalk and the branches they become short, and at the outermost end they are placed close together as quite small projections, whereby the stalk and branches here show a little 8o PORIFKRA. II. s swelling, as described and figured by Sars. Sars says that the branchlets are generally arranged in a circular way, my material is too much damaged to enable me to decide this fact with certainty. The largest of my specimens is, inclusive of the root, 75" ,m high, but the specimen is not quite entire above; the longest branch is 25 mm , and the thickness of the stalk is fully 2 mm . The small unbranched specimens are 33 mm high. Thus this species would seem not to reach any considerable size; Sars gives the height of his specimen to 6o mm , and the specimens from the North Sea and the Gulf of St. Lawrence, mentioned by Schmidt and Lambe I.e., were smaller')- The colour of the sponge '(in spirit) is white or slightly yellowish, often a little transparent; Sars states the colour in fresh speci- mens to be transparently yellow. On account of the axial skeleton the sponge is rather stiff and not very flexible; the outer layer of tissue is soft, and the branchlets are flexible. The surface is smooth, and only at the end of the branchlets projects the supporting fibre. No distinct dermal membrane was seen. Pores were not observed with certainty; here and there on the surface small circular openings were seen, but on account of the bad state of the material I dare not with certainty regard them as pores. Oscula were not found either. Nor have, as it is well known, pores and oscula been mentioned before in this sponge 2 ). The skeleton consists, in the stalk and the branches, of a compact, pohspicular axis, the needles of which are parallel to each other and to the longitudinal direction ; the axis of the stalk, however, is in the lower part somewhat spirally twisted. Below, the stalk, as mentioned, ends in a highly branched root, the branches of which taper more and more, till they end almost with only one spicule, or with a couple of spicules alongside each other. The branches on the stem are not inserted in the axis in the same way, as are the branchlets; it may rather be said that a cleaving takes place, some spicules by degrees bending to the side and forming the branch; in the angle between the stalk and the branches some spicules are found running evenly arcuately between the stalk and the branch, so that the angle is not seen sharply, but as a rounded curve. The skeleton of the branchlets is formed by a fibre pas- sing through the branchlet to its end. It decreases in thickness outward, and accordingly it has here fewer spicules than farther in, most frequently it has here only a couple of spicules alongside. The fibres of the branchlets are inserted in the spicula-axis of the stalk or the branches, between the spicules of these axes, and they pass in to the centre, where, when several branchlets are placed at the same height, they meet. The part of the fibres of the branchlets that is inserted in the axis, is in M Wyville Thomson states (The Depths of the Sea, 112), in a general and, otherwise, somewhat vague mention of C/ador/i/za-spec\es or Cladorhisa-\Cs.e. forms, that they may reach to an extent of 50 — 80cm. He says that at least three species occurred. It is not possible to decide, which species his statement refers to, but I suppose it is to the following ones C. abyssicola is surely not among them, and we see also that the stations mentioned by Carter (Ann. Mag. Nat. Hist. Ser. 4, XVIII, 319), at which Cladorhiza-ioxms were taken, have, all of them, negative bottom temperatures, while abyssico/a occurs on bottoms with positive temperatures. 2 ) Ridley and Dendy (Challeng. Report, 87) say, under the species mentioned by them as C. abyssico/a var. rect- angulai-is: The anatomy of the soft parts of this remarkable species has always been a mystery . I do not see that this is to be said especially of this species. That pores, oscula, and canal-system have not been described is a fact that holds good of many sponge-species, and especially with regard to this sponge Sars has given several details beyond what is known of many other species. When he says that in the layer of tissue absolutely no canals or cavities can be discerned , this of course, is only the expression of the fact that he has not seen them; in the comparatively thin layer of tissue, the canals, no doubt, are small, and scarcely to be observed without special preparation. Ridley and Dendy have not been able to examine their specimen (which otherwise assuredly does not belong to this species) anatomically, as their material was dried, but they have not taken the opportunity either of examining anatomically any of the other C/adoi-Zaza-species they have described. PORIFERA. II. the common way spread in a fan-shaped manner in the longitudinal direction, so that in a transverse section it appears to have only the thickness of a couple of spicides. Accordingly the fibres pass from the middle of the axis through the layer of tissue surrounding the axis, and through the branchlet to its point. In the layer of tissue coating the stalk and the branches, as far as I have been able to see, only rather few, scattered spicules are found. In the stalk and the branches the spicules are cemented by a clear mass of spongin; it coats, no doubt, the whole fibre with a thin layer of spongin, but forms no visible sheath. In the lower part of the stalk it may become somewhat more copious, and then the otherwise white, transparent axis becomes here a little yellowish. In the branchlets no spongin was observed. Spicula: a. Megasclera are styli; they are straight or quite slightly curved; they are fusiform, tapering more or less towards the head-end; not rarely their outer part has a special, but slight taper- ing. The opposite end tapers evenly; the point proper may be somewhat varying, but is always short or rather short, not rarely quite blunt or rounded. The spicules of the axis and the branchlets are of the same form and cannot be said to fall under two distinct groups, but upon the whole there is, however, some difference as to size between them, so that the axial spicules are averagely larger than those of the branchlets. The length of the axial spicules is about 0-5 — 073™™, and the thickness from 0-013 — o-oi9 mm . The spicules of the branchlets are generally 0-39 — o-47 m,n long and 0-007 — ca - o - oi3 mm thick. All kinds of transitional forms occur however. Thus upon the whole a variation is found in the spicules as to length from 039 — o73 mm and as to thickness from 0-007 — o^oig™"". Besides by their size the styli of the branchlets deviate also from those of the axis by having a longer point, and moreover they show also a little curve at the head-end, about as figured and described bv Sars. Sars says that such spicules only occur at the point of the branches; the fact is, however, that they form the fibres of the branchlets, and accordingly they are also found in the points of the branches, where the branchlets are close together; the mentioned curve may otherwise also be found in axial styli. b. Microsclera; three forms occur, anisaneorse unguiferse and sigmata of two forms and sizes. 1. The an corse are of the structure typical of Cladorhiza with a regularly curved shaft and five distinct, narrow, lanceolate teeth in either end; a considerable difference is found between the sizes of the two ends. The larger end has on either side of the shaft a narrow ala somewhat longer than the teeth. A sure view of the number and form of the teeth is only to be obtained by regarding the ancorae from the end. Sars, in the work quoted, says that the ancorse have three teeth, but that some have five, and continues: Whether this applies to all or only to some the position of which happened to be more favorable, I am not able with certainty to decider '). The real fact is that the ancorae have always five teeth in either end. The size of the ancorae is only little varying, their length from ox)2i — o-025 m,r -, and the thickness of the shaft is ca. o - oo2 mm . A few developmental forms of the ancorse were also seen, in the finest ones the ends are as yet only little developed, and they are equal or about so, but a difference in size appears very soon. 2. The large sigmata have a regular sigma-form ; they are always plane or about plane. Their length is between ') It is evident that the opinion of Sars is that the ancorae, what he has not been able to decide with certainty, may possibly always have five teeth, but that this fact is only to be seen, when the ancora? are favourably situated, but his expression, to be sure, says really something different. The Ingolf-Expedition. VI. 2. 1 1 g 2 PORIFERA. II. Q.Qjgmm an( j 'io mm , and the thickness is proportionately 0-005 — o-oo6 mm . 3. The small sigmata are of a peculiar form not mentioned by Sars, about as the form known from sigmata in some of the Asiestoflluma-sipecies, bnt here much more sharply marked. Either end of the sigma from the middle and to the point of the recurved part is highly compressed and inwardly sharpened in an edge-like manner. The sigma is contort, and almost always rather exactly one fourth of a turning. The length is 0-040 — o - 042 mm and the thickness in the middle ca. o-ooi5 mm . The small sigmata, as stated by Sars, occur in the points of the branches in somewhat greater numbers, but besides they occur also in other places of the tissue, but only in very small numbers. The large sigma is stated by Sars to occur scattered in the tissue, and in greater numbers in the points of the branches; this statement I have not found corroborated, but have found this sigma occurring equally frequently everywhere in the tissue, but not especially copiously. The ancorse are present in great abundance, partly throughout the tissue, and especially in the skin or the outer layer; thus they are seen very abundantly in the thin layer of tissue on the branchlets. Embryos. Embryos were found scattered in the tissue in rather great numbers. They are globular and reach a size of ca. o , 35 ,n,n in diameter. They contain no spicules. According to Sars the embryos seem to be developed in the ends of the branches; this fact I did not find corroborated by my material; later, at all events, they are found everywhere in the tissue in great numbers, as has also been observed by Sars. They were also found in the small, unbranched specimens. Remarks: A sure determination of this species is no easy thing, as it is very closely allied to the succeeding ones, and has also constantly been confounded with them. I was long in doubt whether the present species and the following one were specifically different; there are, however, constant char- acters, especially in the size of the spicules, and it was found, moreover, that C. abyssicola occurs only on bottom with positive temperature, while the following species is a native of the cold area. I have not seen Sars's type specimen, but a specimen sent by Dr. Nordgaard, obtained on Sars's old locality, Skraaven, agreed exactly as well with the description by Sars as with my specimens. The species mentioned by Wyville Thomson in The Depths of the Sea , and by Carter in his work on the v Porcupine --sponges as C. abyssicola belong surely, as already mentioned, to some of the succeeding species. With regard to the C. abyssicola mentioned by Armauer Hansen in The Norwegian North- Atlantic Exp. XIII, the fact is most probably that he has not had this species before him at all; all the figures of the exterior show on the contrary that he has had the four following species, gelida, tenuisigma, corticocancellata, and oxeata. and those of the spicula-figures that can be interpreted at all show also that the question is not of abyssicola. I have examined two of his specimens which belonged respectively to the two following species, gelida and oxeata. All the enumerated localities are also seen to be situated in the cold area, with only one exception, and this one is found at the very border of this area. Of the C. abyssicola mentioned by Fristedt (Vega-Exp. vetensk. Iaktt. IV, 455) I have examined one specimen which proved to be C. oxeata. The specimen mentioned by Lam be I.e., on the other hand, is no doubt C. abyssicola, as is obvious from the description; when Lam be says that the ancorre seem only to have three teeth in either end, this is no doubt only owing to the fact that he has not seen them from the end. Finally it must be noted that the two forms mentioned by Ridley and Dendy, C. abyssicola var. rcctangularis with styli up to 2 mm long, PORII-ERA. II. 83 and C. abyssicola var. linearis with three-toothed ancorse o - 032 mni long, may be said with certainty not to belong here, but they must be independent species. Locality: The Ingolf-Expedition has only obtained a slight material of this species; station 32, the Davis Strait, 66° 35' Lat. N., 56 38' Long. W., depth 318 fathoms (bottom temperature 3°9 C), the two largest specimens; station 40, south of Iceland, 62 00' Lat. N., 21° 36' Long. W., depth 845 fathoms (bottom temperature 3°3 C), two small, unbrauched specimens. Geogr. distr. Skraaven at the Lofoten, depth 300 fathoms (Sars), and depth ca. 200 fathoms (one specimen sent by Dr. Nordgaard); the Saltenfjord, depth ca. 185 fathoms (Dr. Nordgaard); the Skager Rack, depth 294 fathoms (O. Schmidt I.e.); between Franz-Josef Land and Nova Zembla 79 15' Lat. N., 59° 14' Long. E., depth ca. 130 fathoms (v. Marenzeller I.e.); the Gulf of St. Lawrence, depth 200 fathoms (Lambe 1. a). Thus the species is known distributed from ca. 60° Long. W. to ca. 6o° Long. E., and between 6o° and 8o c Lat. N. It does not go to specially great depths, the bathymetrical range being between 130 and 845 fathoms, and it is exclusively a native of a bottom with positive tempera- ture. On all the localities the species was taken on muddy bottom, and its richly branched root agrees also with this fact. 2. C. gelida n. sp. PL III, Fig. 1. PL XII, Fig. 3 a— h. 1885. ? Cladorhiza abyssicola Armauer Hansen, The Norwegian North-Atlantic Exp. XIII, Spongiadce, partim, PL VII, figs. 7 b, 10, 12. Slender, will/ branches issuing from a central axis ; the branches arranged more or less distinctly in a plan or issuing quite irregularly; often -eery long and subdivided. The stem ending below either in a roof or a little basal expansion. The skeleton of the type of the genus. Spicula : Megasclera styli 0-40 — 0--/J"""; microsclera of three forms, anisancora- uuguifcrcr with five teeth 0-028— crojj""". sigmatu of ttvo forms, large ones 0-12— o-i6""", small ones, with compressed terminal parts 0-044 — o-oj/""". Of this species we have a rather considerable material, but most of the specimens are rather much damaged. The species is chiefly of the same form and structure as C. abyssicola, but it grows to a considerably greater size, and is more irregular. It consists of a stem, from which lateral branches of varying length issue. The original principle seems to be that the branches issue in one plan to two opposite sides; but this principle is not carried through, and so the branches are frequently arranged irregularly and issue to more sides; the arrangement in one plan, however, is most frequently recognizable. The distance between the branches ma} - be somewhat varying. They issue generally at about right angles, only a little directed upwards. Sometimes the branches are a little swollen towards the end, but often, however, such a swelling is not found. To judge from the material in hand, the stem may end below in different ways, either in the same way as in abyssicola with a branched root, or with a little expansion which then lias been attached; this feature is probably to some degree dependent on the bottom. While in the form now described the sponge is tolerably regular, a high degree of irregularity is very frequent. This irregularity may be owing to several causes. Thus the stem, which in the more regular forms is tolerably erect, may become sometimes irregularly curved, sometimes twisted in such a way, that the branches are lying in all plans. Then the branches ma}- also be bent in many different 84 PORIFERA. II. ways and be of very different lengths, and while in the more regular forms they are most frequently imbranched, they may here be subdivided. Finally anastomoses and coalescences may take place between the branches in the most irregular way, so that the whole thing gets a quite confused appear- ance; nay, even branches from different individuals seem to be able to coalesce. When such anasto- moses takes place, it is always the spicula-axes of the stem and the branches, which touch each other and are coalesced, and the fact is evidently owing to the presence of spongin 1 ). The stem and the branches are set with branchlets or filiform appendages. They issue rather closely to all sides, and no definite arrangement is to be seen. They are frequently directed somewhat upward or on the branches somewhat towards the point, and in different individuals they may be of somewhat different length. With regard to the size to which the sponge may grow it is impossible to say anything definite on the basis of the material in hand, as all the specimens are fragments more or less. In one of the largest fragments the stem has a height of ca. no mm ; another specimen measures, on account of the very long branches, ca. i50 ram ; one of the most irregular fragments, in which stem and blanches could no longer be distinguished, has a greatest extent of 230 mm . The length of the branches, as men- tioned, may vary very much. The stems and branches are of about ecpial thickness, the maximum of which may be given to ca. 5 mm , but it may be somewhat less. The branchlets or the filiform appendages are thin, filiform, and a little tapering outward; their length may be somewhat varying, the maximum is 5— 6 mm , and the thickness at the base does not exceed o^" 1 " 1 . In a few cases branchlets may be found as only exceedingly short, conical projections. On account of the firm axial skeleton the consistency of the sponge is hard, but, especially in the upper parts, somewhat flexible; the outer layer is soft, and the branchlets, in spite of the fibre in them, are soft and flexible. The colour (in spirit) is white to yellowish white. The surface is smooth, spicules project only at the ends of the branchlets. An inwardly distinctly bounded and consequently easily separable dermal membrane is not found; on the other hand the whole layer of tissue is easily separated from the axis. Oscula and pores I have not been able to find, and therefore I take them to be closed. In the layer of tissue nothing is seen of the canal system under slight magnifying powers, but the tissue is apparently of uniform structure, the canals being very small. It is only in thin sections and under higher magnifying powers, that the canals are seen. The skeleton is constructed as in the preceding species, and consists in the stems and branches of a very strong polyspicular axis; the needles of this axis are closely united and connected by spongin. They are chiefly parallel to each other and to the longitudinal axis, the axis, however, is most fre- quently more or less spirally twisted, often so much, that the direction of the needles deviates con- siderably from the longitudinal one. Also in the superficial part of the axis the needles are often not quite parallelly arranged, but may intercross, owing to the fibres of the branchlets being inserted between them. The needles of the axis are turned in different ways, now the point is turned upward, now downward. As in the preceding species the branches are formed by a number of spicules bending to the side, and, at all events, only the middlemost spicules of the branches reach in towards the middle ■) Such irregular anastomoses (at all events in the same individual) seeui to be frequent in the C/ador/tiza-species, and they will thus be mentioned again in the following species. It seems also to be this same feature, which is found in the specimen of the socalled C. aiyssico/a var. linearis, figured by Ridley and Dendy (Challeug. Report, Monaxouida, PI. XX, fig. 6). PORIFKRA. II. 85 ill W of the axis. The central part of the axis may be somewhat looser, or a little cavity may be found here. The skeleton of the branchlets is formed by a fibre running through the middle of the branchlet; the fibre tapers outward, and has fewest spicules at the outer end. When the branchlets are short, the fibre seems to become thicker and have more spicules. The fibres of the branchlets are in the common way inserted in the spicula-axes of the stem and the branches, between the spicules of these axes; they reach to the middle of the axis, and are spread in the longitudinal direction in a fan-shaped way. In the laver of tissue, which coats the axis, and may be of somewhat varying thickness, only rather few, scattered spicules are found. In the stems and branches the needles are connected by a mass of spongin forming, however, no sheath; under the microscope it appears white and clear, but yet it gives to the axis a yellowish, hyaline appearance. The stem has most spongin and is, consequently, most yellowish at the base. In the fibres of the branchlets spon- gin was not observed. Spicula: a. Megasclera are styli, straight or quite slightly curved; they are more or less fusi- form, but most frequently slightly so, only tapering a little towards the head-end; the point is some- what varying, from short, some- times somewhat blunt, to middle long. Their length varies from 0-40— o77 mm and the thickness about from o - o22 mm clown to o - oi 1""". The spicules are upon the whole larger and specially thicker in the axis than in the branchlets, but they cannot be said to form two groups. The styli of the branchlets have also a somewhat longer point. Otherwise the length and thickness are in no proportion to each other, and styli are rather frequently found in the axis of the smallest length, but of the greatest, or about the greatest thickness, while on the other hand long styli may be consider- ably fine. In the branchlets and the layer of tissue spicules may be found that are considerably finer than the others and must be developmental forms, they are long pointed. Among the styli, especially in the branchlets, irregular forms are often seen; thus, but more rarely, oxea; more frequently forms are seen with one or more swellings, b. Microsclcra; three forms are found, anisancoras ungmferse and sigmata of two forms and sizes. 1. The ancorEe are of the typical CladorMza-stxuctuie, and have live distinct, lanceolate teeth in either end; one end is considerably larger than the other. The larger end has on either side of the shaft a narrow ala a little longer than the teeth, but comparatively Fig. 2. Cladorhiza gelida 11. sp. Transverse section. The branchlets being directed a little upward, the fibres issuing from the centre are only seen a little way out in the tissue, where they are then cut away, while the fibres seen in the branchlets issue more downward, so that their bases are not seen. In the tissue embryos are seen. X ca. 32. 85 PORIFERA. II. .somewhat shorter than in abyssicola. The size of the ancorte varies between 0'028 — o-034"" n , by far the most frequent size is o-03i mm , the thickness in the middle of the shaft is ca. o-oo3 mm . Developmental forms of the ancorse occur frequently in all stages, down to extremely fine ones, which are of about the same length as the fully developed ones; in the very youngest stages both ends are as yet equal 1 ). These voungest stages show in either end apparently only a hook-like recurving (PL XII, fig. 3 d) which must, accordingly, be taken to correspond to the median tooth; but they are so fine and transparent, that the real form of the end cannot be seen with certainty; in the stages a little older the teeth are seen. 2. The large sigmata are of a regular sigma-shape, they are plane, or only slightly contort. Their outer part, the recurving and the hook, is not quite cylindrical, but somewhat compressed. They vary in length from cri2 — o-i6 mm , and in thickness from croo6 — o-oo9 mm . Developmental forms in different stages of these sigmata were not rarely seen; the younger of these are more or less fine, evenly curved, and long pointed staves without recurved ends; the ends are only developed by and by. Also the develop- mental stages show the compression of the ends, and these are sharp inward. 3. The small sigmata are of the same peculiar form as in abyssicola, with compressed ends, inwardly sharpened as edges. They are likewise always contort to one fourth of a turning. Their length is 0-044— o-05i mm , and the thickness in the middle is ca. o - ooi5 mm . The occurrence of this sigma is peculiar. It occurs always only very sparsely, so that pieces of the sponge may be examined without any being found; but sometimes this form of sigma seems to be quite wanting; thus in some specimens I have examined a great number of pieces without being able to find it. Otherwise it is found sparsely in the tissue without any such definite occurrence as in abyssicola. Neither does the large sigma occur in great numbers, but consi- derably more copiously than the small one; it occurs in the layer of tissue and especially in the skin. The aucorae are present in exceedingly great numbers, partly throughout the layer of tissue, but especially in the skin or the outermost layer; they are especially closely packed in the thin layer of tissue on the branchlets. Embryos. Round in the tissue embryos were found ; the}' lie singly in the layer of tissue between the axis and the surface. They are all but globnlar and of an average size of ca. o - 3' mn . No spicules were found in the specimens examined. This species, as will have been seen, is very closely allied to abyssicola, and it is mainly sepa- rated from it by the constant difference in size of the three forms of microsclera. As mentioned under the preceding species, I have seen a specimen from the material of The Norwegian North-Atlantic Expedition of the species mentioned there by Armauer Hansen as C. abyssicola. It was a small fragment, very much damaged, but it seems doubtless to belong to the present species. The size of the ancorse is generally o-028 n,m , and that of the small sigmata o-o44 m,n . The specimen was from station 31 with a bottom temperature of -^-i°oC. Of the figures of the exterior in The Norwegian North- Atlantic Expedition PI. YD, figs. 7 b, 10, and 12 would seem to belong to the present species. An M Carter, as is well known, advanced the theory that the anisochela; in their development pass through an iso- chelate stage, because in a few species he had found large anisochehe and small isochelae together. He got this view on account of his erroneous interpretation of the growth of the chete. The fact that forms as the anisancora; of the Cladorhi=a begin with a stage where both ends are equal cannot, of course, corroborate Carter's 'theory, as his opinion was that an isochelate stage fully developed as to form preceded the fiual, anisochelate one. PORIFERA. II. 87 attempt to interpret the given spicula-figures, would, I suppose, show figs. 3, 7, 8, 9, 11, and 12 on PI. IV to belong to the present species, but the interpretation is doubtful. Locality: The Ingolf, station 112, 67° 57' Lat. N., 6° 44' Long. W, depth 1267 fathoms (bottom temperature -=- i°i C.|; station 113, 69° 31' Lat. N., 7 06' Long. W., depth 1309 fathoms (bottom tempera- ture -f-i°oC); and at 60° 19' Lat. N., 5 39' Long. E., depth 620 fathoms (bottom temperature ca.-^-o°i5C.) (Ad. Jensen, the cruise of the Michael Sars 1902). The two first localities are situated in the Nor- wegian Sea about between Jan Mayen and Iceland, the last one in the Faroe Channel. Geogr. distr. Besides on the mentioned localities, the species, as before mentioned, has been taken by the Norwegian North-Atlantic Expedition at station 31, 63° 10' Lat. N., 5 J 00' Long. E., depth 417 fathoms. Presumably it has been taken at more places by this expedition, but, at all events, always in the cold area. Accordingly the species is known from the Norwegian Sea and from the Faroe Channel with a bathymetrical range from 417 — 1309 fathoms, and it occurs only on cold bottom. I supijose that the species is also found among the Cladorhiza-iorm* from the Faroe Channel mentioned by Wyville Thomson in the Depths of the Sea 112 — 113. 3. C. tenuisigma n. sp. PI. Ill, Figs. 2—5. PL XII, Fig. 4 a— e. 1885. ? Cladorliiza abyssicola Armauer Hansen, The Norwegian North-Atlantic Exp., XIII, Spongiada;, partim, PI. IV, fig. 14, PL VII, fig. 11. Slender, with branches issuing from a central stein, the branches oftenest distinctly in one plan tn two sides, most frequently long and ending in a swelling. The branchlets more or less distinctly arranged in a ring-like manner. The stem ending below in a richly branched roof. The skeleton of the generic type. Spicula: Megasclera styli o-j8 — roi"""; microsclera of three forms, anisancorcr unguifcra* with five teeth 0-024 — 0-028""", sigma/a of two forms, fine ones of the common form 0-038 — 0-048""". sig- mata with compressed terminal parts 0-048 — o'ojd""". In the exterior and skeletal structure this species is very similar to the preceding one, but it is distinguished by characteristic differences as well in the exterior as in the spiculation. It is formed of an erect stem ending below in a densely and richly branched root. In the specimens in hand that are possessed of the root it is formed in such a way, that the stem continues quite down to the lower part of the root, and only here is divided into branches, while from the lower part of the stem thicker close-set branches continually pass of, and again subdivide to a high degree. The finest branches end with the thickness of one spicule. In the specimens in hand the radical branches issue only to one side, so that the whole radical tuft is turned to that side (PI. Ill, fig. 3). To the radical branches, especially to their outer part, some bottom material, as pebbles and especially Foraminifera in great numbers, is attached. These bodies stick rather firmly, and seem to be kept by the spongin present in the root. Lateral branches issue in the common way from the stem. These branches issue with varying intervals, and ma} 1 in this respect issue in a rather irregular manner; sometimes, however, they are placed in a tole- rably regular way. They go off at about a right angle or are a little directed upward. The branches may be of varying length, but generally they are very long. In a few cases the branches may again carry PORIFKRA. II. some short branches, and irregularities caused by anastomoses and coalescing of branches may occur, but both these features seem to be found only rarely. The branches are generally arranged in a distinctly bilateral way, but here and there a branch ma} - be placed in a different plan. The bilaterality is effaced in only one specimen, in which the branches are very close-set, but this specimen is upon the whole somewhat irregular. As in the preceding species, stems and branches carry branchlets. These branchlets are in this species more close-set than in the preceding one, and besides they are here arranged more or less distinctly in a ring-like way. This arrangement is not always marked, but is in all cases recognizable; sometimes the circles pass into each other, and then there is a beginning spiral arrangement. The number of the branchlets in the circle is generally some half-score. The branchlets pass off at right angles, or are, especially in the outer part of the branch, directed towards the point of the branch. Their length may be somewhat varying, from rather long, outwardly thread- fine ones, and to quite short, comparatively thick projections. The branchlets of the same circle are more or less coalesced at the base, and when the}- are quite short the branches get a peculiar jointed appearance, and may to some degree remind of the arm of an Ophiurid. In a few places of the stem or the branches the branchlets may be quite wanting, and these parts are then slightly shaggy. The branches end at the point in a globular or ovate swelling, below which the branches are a little con- stricted, by which means the swelling becomes more sharply marked off. The last branchlets before the swelling decrease a little in length. One of the tolerably whole specimens, which is, however, not quite undamaged above, has a height of ca. ijo" 1 " 1 , and most of the other specimens seem to have been of a somewhat similar height. The specimen which seems to have been the largest one is only a little higher, but it is broken off below, and a rather large piece is no doubt wanting. The length of the branches may, as mentioned, be somewhat varying, the greatest length measured was 80 — 90""". The stem and the branches may be of somewhat varying thickness, but they are generally compara- tively thin in proportion to their length, and so the species gets a more slender appearance than the preceding one; the thickness, which is about equal in stem and branches, or only a little greater in the stem, may be given to 2 — 5 mm . The branchlets vary from quite short projections to 8 ,nra long, threadfine appendages. The consistency is as in the preceding species. The colour (in spirit) is whitish to whitish vellow. The surface is upon the whole smooth; at the points of the branchlets the fibres project, and the terminal swelling of the branches as well as the parts of the branches that show no branchlets are slightly shaggv. Outermost a very thin dermal membrane is found, only distinct in the parts between the branchlets; it is supported by spicules underneath, but cannot be separated alone. Pores are found in the dermal membrane, especially in the parts between the branchlets; they are often very close-set. They were measured from quite fine openings to a diameter of ca. o-o6 mm . Pores are also found in the swollen terminal part of the branches 1 )- Oscula have not been observed. In transverse sections of the sponge canals are seen in the layer of tissue between the fibres of the branchlets; these canals run chiefly as longitudinal ones, and being the widest canals seen it is an ■) If pores have not hitherto been mentioned in the Cfadorkisa-species, I suppose that it is only owing to the fact that they are only to be seen with difficulty. The fact is that the outermost layer consists of close-lying membrane-like parts separated by narrow cavities; the outermost membrane forms the dermal membrane. The pores in this membrane, accord- ingly, lead into a cavity inside, and the cavities are connected with each other by pores in the membranes. Now the der- mal membrane proper cannot be separated except by special preparation, and if we cut off a piece of skiu-layer ever so thin, we shall nevertheless get more than the outermost membrane, and so the pores are not seen by transmitted light. PORIFERA. II. 8 9 obvious conclusion that the}- are excurrent canals; if so, we should expect to find oscula at the points of the branches. It may, however, also be possible that among the mentioned pores some may act as incurring openings, others as excurrent ones. The skeleton is chiefly constructed as in the preceding species. It consists in stem and branches of a powerful axis which is also here somewhat spirally twisted, especially in its lower part. The lateral branches are formed in the common way. The skeleton of the branchlets is formed by a fibre more or less long according to the length of the branchlets; in the long branchlets the fibres are out- wardly very fine, and outermost they have only quite few spicules. The fibres of the branchlets are inserted in the axis in the common way. As the branchlets are arranged more or less circularly, their fibres, in a transverse section passing through a circle of branchlets, are all seen to go to the middle of the axis like the spokes of a wheel. When the layer of tissue with the branchlets and their fibres is removed, so that only the axis is left, this is seen to be transversely striated on account of the circular arrangement of the branchlets, the part of their fibres that is inserted in the axis appearing as darker circles when the other part is removed. The axes of the branches continue through the middle of the swollen terminal part, and at the outer end they spread in a somewhat peuicillate way. From the part of the axis running through the terminal knob rather regular, thin fibres issue to the surface, through which their outer ends project quite slightly (Woodcut fig. 3). Thus the whole terminal knob may be regarded as a collection of coalesced branchlets. Between the mentioned fibres in the terminal knob are moreover found some scattered spicules. In the above mentioned places of the stem and the branches where no branchlets are found, fibres are nevertheless found as in the other places, inserted in the axis in the same way, and these fibres continue into the layer of tissue, which is, besides, highly filled with spicules some of which are running chiefly longitudinally, while most of them are situated irregularly. Some of these spicules project a little through the surface. In these places the layer coating the axis is of greater thickness, so that it may more likely be regarded, as if the branch- lets were coalesced to one layer. In the layer of tissue which coats the other part of the axis, spicules are found rather copiously of which some are running longitudinally, while a great part are irregularly scattered; the dermal membrane is supported by the outermost ones of these spicules. Where the branchlets are long there are the fewest spicules in the layer of tissue; the shorter the branchlets are, the more spicules are found in the layer of tissue, and the greatest number of spicules are found where the branchlets are quite wanting. In the stems and branches the needles of the axes are cemented by a clear mass of spongin, giving to the axes a slightly yellowish colour. Spicula: a. Megasclera are styli, straight or almost straight; they are fusiform, tapering evenly towards the rounded end, and towards the point to about the same degree; therefore the point itself is short, but it may be more or less blunt and is sometimes rounded. There is no distinct difference The Ingolf-Expedition. IV. 2. 12 Fig. 3. Cladorhha ienuisigma n. sp. Longitudinal section through the end-swelling of a branch showing the skeleton, x 10. - n PORIFERA. II. between the styli of the axis and those of the branchlets and the layer of tissue, the styli of the axis being only upon the whole a little longer and especially a little thicker. With regard to the length styli may be found in the branchlets as long as the longest ones in the axis, but upon the whole they are shorter, and styli may be found here considerably shorter than are generally found in the axis; also are the styli of the branchlets almost always longer pointed. The length varies at most from ca. 0-58 — roi m,n , and the thickness from ca. 0-014— o-0257 mm . With regard to the axial styli the length rarely goes below 070 ,nm , and the greatest thickness attained by the styli of the branchlets is ca. o-02i mm . In the branchlets long, fine styli with long points occur rather frequently, which are, no doubt, developmental forms, b. Microsclera are anisancorse unguiferae with five teeth and sigmata of two forms. 1. The ancorae are of the common Cladorhiza-type, and are constructed quite as in the preceding species. Their length is 0-024 — o-028 mm , and the thickness of the shaft in the middle o-oo28 mm or a little less. Developmental forms in different stages are rather frequent. 2. Sigmata of the first form are fine, of the common sigma-form; they have a somewhat curved shaft and regularly round-curved ends; they are contort up to the fourth part of a turning, most fre- quently, however, somewhat less. They have not the edge-like expansion occurring in the other form of sigma, but are not, otherwise, quite cylindric, but seem to be somewhat compressed through their whole length. Their length is 0-038— 0-048™"', and the thickness about 0-0014"™. 3. Sigmata of the second form have a similar form as, and correspond to, the smaller sigmata of the two preceding species; they have an almost straight shaft, and their ends are somewhat compressed, but to a far smaller degree than in the preceding species. They are contort and always one fourth, or about one fourth, part of a turning. Their length is 0-048— o-056 mm , most frequently nearest to the smaller size. The thickness is about o-oo25 mm . The two forms of sigmata are easily distinguished; the former is especially distinguished from the latter by being finer and having no expansions towards the ends, by its curved shaft, and by its being generally twisted less than one fourth of a turning. It can only be confounded with developmental forms of the second kind. The two forms occur in distinctly limited parts of the sponge; sigmata of the first form occur in the tissue of the whole sponge, except in the end-knobs; in these, on the other hand, sigmata of the second form are exclusively found, and in copious numbers; but none of the sigma- forms occur in anything like the number of the ancorae, which are present in great abundance throughout the tissue, especially in the dermal layer. Embryos. Embryos were found in most specimens of this sponge. They are lying in the tissue outside the axis, often rather closely, but each in a cavity of its own, and each embryo is surrounded by a membrane. They are globular or somewhat oval, and of a diameter of up to o'5 m:n . The spicu- lation is different in the different stages ; some have no spicules, others only ancorae, and others again have both ancorae and styli. The ancorae are smaller than in the developed sponge, most frequently of a length of 0-017— o-02i mm , and also rather fine. The styli are likewise small and very fine. The styli are arranged in a bundle about in the middle of the embryo, while most of the ancorai seem to be chiefly placed in the circumference. None of the two forms of sigmata were seen in the embryos. This species is very similar and closely allied to the preceding one; in its outer form it is especially distinguished from the former by the more or less marked circular arrangement of the PORIFERA. II. 91 branchlets. With regard to the spiculation sure distinguishing characters are found in the sigmata, especially in the presence of the fine, contort sigma, and in the size of the ancorse. Among the figures of the exterior, given in the Norwegian North-Atlantic Expedition, those quoted above may with great probability be referred here, especially on account of the distinctly figured end-knobs. Of the figures of spicula, fig. 6 on PL IV may with some probability be referred to the present species. Among the Cladorhi:a-iovms taken by the « Porcupine -Expedition, I suppose that the « peculiar form in jar 65 mentioned by Carter (Ann. Mag. Nat. Hist. Ser. 4, XVIII, 320) belongs here; according to the descrip- tion it might very well be a specimen with small or wanting branchlets. Locality: Ingolf station 105, 65° 34' Lat. N, f 31' Long.W., depth 762 fathoms (bottom temperature -r-o°8C); station 117, 69 13' Lat. N., 8° 23' Long. W., depth 1003 fathoms (bottom temperature -4- i c o C), seven more or less damaged specimens in all. Station 105 is situated to the east of Iceland, and station 117 south of Jan Mayen. Gcogr. distr. The species is hitherto with certainty only known from the Norwegian Sea, where, besides by the « Ingolf , it has been taken by the Norwegian North-Atlantic Expedition. If the form mentioned by Carter I.e. belongs here, it has also been taken in the Faroe-Channel at a depth of 345 fathoms with a bottom temperature of -4- i°i C. Accordingly, the species is, at all events, a native of the cold bottom. 4. C. iniquidentata n. sp. PL III, Fig. 6. PL XII, Fig. 5 a— e. Slender, with branches issuing from a central axis ; the branches rather long, not arranged in one plan, swollen in the ends in a somewhat club-shaped way. The skeleton of the generic type. Spicula: Megasclera styli o-jo — o-68"""; microsclcra of only one form, auisaneora 1 nnguifcrcc with six to nine teeth in the larger end, five teeth in the smaller end. 0-022 — 0-024""". In the exterior this species is very similar to C. abyssicola. We have only one specimen con- sisting of a slender stem carrying a number of thin lateral branches issuing irregularly with different intervals. The specimen is broken as well above as below, so that nothing can be said of its mode of attachment. The stem and branches carry in the common way close-set branchlets issuing all round. These branchlets are a little directed upward, but in contradistinction to those of the preceding species they are quite straight. They are thickest at the base and become quite thin outward. A distinct circular arrangement was not to be observed; but they are to some degree arranged in groups, and this arrangement gets more marked by the fact that the branchlets are often coalesced at the base, so that irregular circular thickenings are found, from which the branchlets issue. Towards the point of the lateral branches the branchlets become shorter, and the points of the branches are slightly swollen in a club-shaped way. The specimen in its damaged stage has a height of 50 mm , the only entire lateral branch measures 27 mm , and the branchlets, which may be of somewhat different lengths, are at most 3-5 mm long. The stem is fully i ,nm thick, the lateral branches are a little thinner. The colour (in spirit) is whitish, somewhat transparent. The sponge is rather stiff, and the branchlets scarcely so flexible as in the preceding species. The surface is smooth, spicules are only projecting in the points of the branchlets. A thin dermal membrane ma}' be observed. Pores are seen in the 12* 9 2 PORIFERA. II. dermal membrane in the intervals between the branchlets 1 ); they were measured to a size of at most Q.j.nm. t he largest ones seemed especially to occur in the parts of the skin that cover the upward turned parts of the coalesced bases of the branchlets. Oscula have not been seen, but the larger of the men- tioned pores may possibly be excurrent openings. The skeleton is constructed as in the preceding species; it consists in the stem and branches of rather strong, polyspicular axes. The fibres of the branchlets are in fhe common way inserted in the axes, and continue to the middle; they grow thinner and have fewer spicules outward, and they end, when the branchlet is long and thin, with a few spicules or a single one. In the layer of tissue coating the axis only a few, scattered spicules are found partly lying in the longitudinal direction, by which spicules the dermal membrane is supported. In the axis the spicules are cemented by a distinct mass of spongin. Spicula: a. Megasclera are straight, or quite slightly, sometimes a little irregularly curved styli; they are markedly fusiform, tapering somewhat, not only towards the point, but also towards the rounded end. The point itself is short and bounded by straight lines; it may be of somewhat varying length, and in a few cases it is rounded. There is no difference between the styli of the branchlets and those of the axes, only may the latter as a whole be a trifle thicker, that is to say: some of them may be a little thicker, and there are between them scarcely so thin styli as outside the axes. Their length is from ca. 0-50— o-68 mm , and the thickness varies from 0-014— o-026 mm . Finer to quite fine developmental forms occur in small numbers, b. Microsclera are only of one form, anisancorse unguiferae; they are typical Cladorhiza- ancorse of the common form with a regularly curved shaft and a narrow ala on either side of the shaft at the upper end. They are, however, peculiar by their number of teeth. In the large end the number of teeth is not constant; most frequently the number is seven, not rarely, however, eight; in a few cases it was six, in some others nine. The teeth are close-set and narrow. The small end, on the other hand, has only five very small teeth. With regard to both ends it is impossible to decide the number of teeth, unless the ancorse The length of the ancorse is 0-022— o-024 mm , and the thickness of the shaft is ca. o-oo2 mm . Developmental forms of the ancorse occurred in different stages. The ancorse occur in the tissue and in the skin; as usual they are especially copious in the branchlets. Embryos. Embryos were found scattered in the sponge; they are roundish or oval, and averagely of a diameter of ca. o-24 ,r "". They occur both in the stem and branches in the tissue outside the axis. They were often seen at the base of the branchlets or even a little way out in the branchlets (Woodcut fig. 4). If the larger of the pores mentioned before act as excurrent openings, it may easily be understood that the embryos are found near them 2 ). The spiculation of the embryos is very interesting. They were either ') They -were only seen in dried preparations. -1 When the embryos are found in the lower part of the branchlets themselves, it is seen that this part is hollow, and the spicules of its fibre surround the embryos on all sides; farther out the spicules unite and form a fibre in the common way. According to this the fact is not precluded that the embryos leave the sponge through the branchlets, and by this Fig. 4. C/adorhiza iuiqui- dentata u. sp. One of the branchlets with three embryos. X 20. are seen from the ends. PORIFERA. II. 93 without spicules, or they had microscleres, or else both microscleres and megascleres. The megascleres are small, rather fine and straight styli, arranged like a bundle through the middle of the embryo along its longer axis. The microscleres are very peculiar: they are ancorse, but of a type different from that of the grown sponge. They are smaller and finer, and their teeth are considerably longer than is commonly the case in the Cladorhiza-a.ncor2£\ these teeth, which are very narrow, reach to about the middle of the ancora, or at all events, more than a third of the length. At the larger end there is on either side of the shaft a narrow ala of about the same length as the teeth. Nor is the number of teeth in the larger end constant in these ancorae, but it may be five or six, while in the smaller end the number is always five. The length of these ancorae varies from 0-017 — 0'02i mm , the thickness of the shaft is ca. o-oon" 1 '". I do not venture to decide, whether the final form of ancorse is formed, while the embryo is still in the sponge; ancorae of the final form and size were certainly found in a single case; but as the embryos are only isolated with difficulty they may have belonged to the surrounding membrane. — That embryonic microscleres of a special type occur is a quite peculiar fact, and has not hitherto been observed; the microscleres of the embryos, as has repeatedly been pointed out in the preceding descriptions, are often smaller than in the grown sponge, but they are generally of quite the same form. This species is easily recognizable from the other Cladorktza-species by its ancorse. Hitherto no Cladorhiza-species has been described with ancorae with more than five teeth, while here seven or eight teeth are found. A peculiar fact is also that the number of teeth is not constant. When seven teeth are found, one is consequently the median one, but when eight teeth are present, the feature seems to be different, as also then one tooth may be the median one, and then there are consequently four teeth on one side, of which a pair then seems to be a little smaller than the others, as if a cleaving had taken place. In other cases no median tooth is found, but there are four teetb on each side of the median line. In the embryonic ancora there seems always to be a pair in the middle when six teeth are found. A remarkable fact is finally the different number of teeth in either end, as it would seem that the smaller end, without regard to the greater number of teeth in the larger end, has constantly five teeth; while, on the other hand, to judge from the species with three-toothed ancorae described by Ridley and Dendy, it has only three teeth, when the large end has this number. Locality: 63 13' Lat. N., 6° 32' Long. W., depth 975 fathoms (bottom temperature -;- o°5i C.) (Ad. Jensen, the cruise of the Michael Sars» 1902). According to this the species is a native of the cold area. 5. C. corticocancellata Cart. PL III, Figs. 7—9. PI. XII, Fig. 6 a— f. 1876. Cladorhiza abyssicola var. corticocancellata Carter, Ann. Mag. Nat. Hist. ser. 4, XVIII, 319, PI. XIII, figs. 16, 16 a. 1885. Cladorhiza abyssicola Armauer Hansen, The Norwegian North-Atlantic Exp. XIII, Spongiadae, partim, PI. IV, fig. 10, PI. VII, fig. 7 a. Erect, set with a number of short, almost zoart-likc projections or branches; otherwise unbranched. or divided into branches from the base. The surface is oj a peculiar, reticulate-grooved structure, and no possibility we are again led to reflect on a connection between oscula and branchlets, as has been hinted at before under Asbestopiuma pennalula and the following slsdes/ofi/uma-species. 94 PORIFERA. II. braiiclilcts arc found. The skeleton is of the typical Cladorhiza-structure, and consists of a central axis with lateral axes and fibres for branchlels ; but all these features are covered by the tissue, which thus forms a coating layer, from which only the short wart-like ends of the brandies project. Spicula: Mega- iclera styli o-^6 — o"ji"""; microsclera of three forms, anisancorm unguifera with five teeth o-ojj—o-ojj""". sigv/ata of tzvo forms, large ones with slightly curved shaft and the ends prolonged in a flagelliform manner o-i$ — 0'i8 mm , small ones with compressed terminal parts o-o^f — o-oj-f""". This species has a peculiar appearance, quite deviating from the other Cladorhisa-species. It is of erect form; whether it is fixed below by an expansion or attached by a root is not known, as my speci- mens are broken below, and Carter's description is based on fragments. The species ma}' be described as a stem, set closely and all round with short, thick, more or less coalescing branches. Most frequently the branches are so short, that they may better be described as wart-like projections, only rarely they are a litte longer. As the}' are placed closely and irregularly, the sponge gets a more or less tuberous or round-lobed surface. The specimens in hand have, otherwise, an erect form, and are straight or a little curved, and besides the mentioned branches they have no ramifications; some skeletal parts, how- ever, indicate that the sponge may also divide into larger branches each of which is then of the described form. The largest specimen has a height of ca. 28o mm , and the others are a little smaller. The thickness, which, on account of the close-set, round-lobed projections, can only be given approximately, is 10 — 20 inm . The length of the branches is at most i3 mm , and their thickness at the base up to o, mm . On account of the powerful axes the sponge is stiff, also the consistency of the tissue is rather firm, but brittle. The colour (in spirit) is yellowish white. The surface is of a peculiar structure; as ends of fibres are projecting everywhere it is shaggy or prickly. Deep grooves or canal-shaped cavities going into the sponge are found between the ends of the fibres, so that the surface gets a reticulate-grooved appearance, what has been expressed by Carter in the name corticocancellata. The points of the branches are generally rounded, and they have no grooves, but show an even surface, shaggy from slightly pro- jecting spicules. All the part of the sponge that coats the axes is penetrated by a system of canals and cavities connected with each other, but separated by parts and beams of tissue, and these canals and cavities must be supposed not to belong to the canal system proper. As this structure is closely connected with the skeletal structure, a more particular account of it will be rendered under the description of the skeleton. The dermal membrane is a thin film covering the parts of tissue that separate the mentioned cavities, and supported by some spicules. Pores and oscula ■■ As the mentioned canals and cavities must be supposed not to belong to the canal system, their outer openings cannot be oscula. Pores are found everywhere in the dermal membrane in the mentioned cavities; they seem to be small, as I have not with certainty measured any of them to a greater size than oo65 mra ; I sup- pose that these openings act both as incurrent and excurrent ones. Of course, it is possible that some of the openings on the surface may be openings of real, excurrent canals; but this fact is scarcely to be decided by an anatomical examination only. The skeleton. In spite of the deviating exterior form, the skeleton is constructed after quite the same principle as in the other C la do rh/za -species. A thick, powerful , polyspicular axis of closely united, parallel needles stretches through the middle of the sponge. This axis has below a thickness of 4""". It is more or less spirally twisted, especially in its lower part. Lateral axes a little upward PORIFKRA. II. 95 directed issue from this axis in the same way as in the preceding species. These axes run through the middle of the short lateral branches before mentioned, and accordingly they attain only a rather small length. Fibres issue from the axes of the stem and the branches, quite corresponding to the fibres of the branchlets in the preceding species. They issue all round, and most frequently they are arranged in a more or less circular way, and they are inserted in the axes in the common manner, so that in a transverse section they are seen to meet in the middle (Woodcut fig. 5). The circular arrange- ment cannot be seen in the exterior, but when the layer of tissue is separated from the axes, a ringlike structure is seen in these, owing to the basal parts of the small axes, which are inserted into the axis (PI. Ill, fig. 8). Now the only difference between this species and the preceding ones is that while in these the fibres inserted in the axes support free branchlets, they support in the present species the coherent part of tissue on the stems and branches, continuing from the axis out through this tissue, and their ends projecting a little. These fibres are in this species of about the same thickness through- out their length; sometimes they are a little curved. They may be somewhat branched, especially in their outer part, so that the number of projecting ends is greater than the number of fibres inserted in the axis. The part of the sponge coating the stem and the lateral branches and supported by the mentioned small fibres is not solid, but is, as before mentioned, pierced by a coherent system of cavities. A row of cavities is especially found inmost, round the axis, arranged like stories above each other, separated by the almost plate-shaped parts of tissue in which the small fibres run, but still connected with each other. Accordingly, a longitudinal section of the sponge reminds strikingly of the chambered root-stock of Cicuta virosa & ' Cart. (PI. Ill, fig. 9). In the outer part of the layer of tissue the cavities A piece of a transverse section showing are more canal-shaped, and they open everywhere on the outside tte axis and * e ^all fibres, m the * tissue embryos are seen, x 7. with round or roundish openings between the projecting ends of the fibres; their being at the same time connected with each other gives rise to the mentioned netlike structure. A comparison with the other species of the genus and especially the correspondence in the skeletal structure imparts the impression that the sponge-body coating the axes must be regarded as having arisen by a coalescing of branchlets, or must, at all events, be corresponding to coalesced branchlets, and that the mentioned system of cavities and canals, therefore, does not belong to the canal system proper, but is a secondary formation. This is also indicated by the fact that the cavities are abundantly connected with each other, so that one cavity in the sponge opens on the surface by several ways and to different sides. Whether free branchlets are found at any time during the growth of the sponge, and whether a real coalescing takes place, or the mentioned structure appears from the beginning, I am not able to decide, as I have had no young individuals 1 !. The described regular "I I have later seen a specimen which was surely a rather young one, and as it showed partly free branchlets, which were chiefly connected oniy near the axis, this seems to indicate that the above described condition develops during the growth of the individual. 9 6 PORIFERA. II. formation and arrangement of the skeletal axes may in certain places be .somewhat modified by coalescings between the axes and the small fibres of the stem and the branches in near the axis of the stem, so that in these places a quite irregular network of fibres is formed (PL III, fig. 8). These coalescings, which are evidently secondary ones, seem to me to corroborate the view advanced above by showing that coalescings easily take place. Outside the axes and the small fibres a great number of scattered spicules is found in the tissue; they may here and there gather into bundles or short fibres, and the}' support also the dermal membrane as a rather dense, but irregular network of scattered needles. In the axes a tolerably copious, slightly yellowish mass of spongin is found imparting to the axes a yellowish, hyaline appearance. Spicula: a. Megasclera are styli, almost always quite straight; they taper somewhat towards either end, and are therefore markedly fusiform ; the rounded end may be more or less thin, sometimes it shows outmost a more abrupt tapering. The point may vary somewhat in length, but is always short or rather short, a more abrupt, distinct point being found besides the even decreasing in thick- ness from the middle; sometimes the outermost point is especially marked off. There is no difference between the styli of the axis and those of the other parts of the body. The length is rather constant and varies from ca. 0-56- 071""", and the thickness from ca. 0015 — 0'024 mm . Finer developmental forms are onlv seen quite singly, b. Microsclera are of three forms, anisancorae unguiferse and sigmata of two forms, larger and smaller ones. 1. The ancorse are of the common C la dor h/za -lor m and have five teeth at either end; at the larger end rather broad alse are found somewhat longer than the teeth. Sometimes six teeth are found at the larger end. The length varies from 0-033— o-037 min , and the thick- ness of the shaft is about croo28 min . Developmental forms in different stages are also found. 2. The large sigmata are of a quite peculiar form, the shaft is only slightly curved, the recurved ends are prolonged in a flagelliform way to a fine point. The surface of the sigma is a little uneven, so that the contour appears somewhat undulated, especially in the middle. The ends are not cylindric, but a little compressed. The sigma is contort to a somewhat different degree, most frequently up to about one fourth of a turning. The length is between 015 and o-i8 mm , and the thickness in the middle of the shaft is ca. ooo7 mm . Of this sigma a few developmental forms were seen, the youngest ones only representing the shaft without curves, those a little older having short curves; in the latter the compressed form of the ends is distinctly seen. 3. The small sigma occurs only in the ends of the branches, and has from this fact, I think, been overlooked by Carter. It is of a quite similar form as the sigma occurring in the same way in the preceding species, for instance tenuisigma, and evidently corresponds to this sigma. The shaft is about straight, the ends are recurved and a trifle compressed about from the middle of the sigma. The sigma is contort, most frequently one fourth of a turning. The length is 0-057— 0'074 mm , and the thickness in the middle is ca. o-oo2 mm . The aucoras and the large sigma occur everywhere in the sponge, especially in the dermal membrane everywhere in the cavities; the small sigma, as mentioned, occurs only in the points of the branches and in rather small numbers. Embryos. Embryos are found in great numbers everywhere in the sponge. The)- are more or less oval and a little flattened. Their longest diameter is on an average ca. 0'42 mm . They were found partly without spicules, partly with microscleres. These were ancorse, and as in the preceding species we have again here the peculiar fact that these ancorae are of a different type from those of PORIFERA. II. 97 the grown sponge. They are very small and fine, with five teeth in either end; those of the larger end are narrow and long, they are thus more than one third of the length of the shaft, while in the ancorae of the grown sponge the teeth are only about one fifth of the whole length. At the larger end a narrow ala is found on either side. This ancora is very small, of a length of only abont o-oi8 mm . In the embryos where it is found, it occurs abundantly. This species agrees so exactly with Carter's description and figures, that there can be no doubt of the identity. The figure of the characteristic sigma agrees completely, and the measure given by Carter (.39 by 1 — 6000th. inch », which is about corresponding to the length o-i64 mm and the thick- ness o - oo4 mm , corresponds also. Finally, the locality is the same. As before mentioned, it may easily be explained that Carter has not found the small sigma, as it occurs only in the points of the branches. Two of Carter's statements do not agree with what I have found; in the first place he states that the styli are larger in the fibres of the stems than in the small fibres, while I have found no difference in size; this fact, however, is scarcely of any importance; but then he gives the size of the styli as < 100 by 1 — 1800th inch. , which is about corresponding to a length of i"4 mm and a thick- ness of o-oi4 ,mn ; this is a little thinner than, and twice the length of, the measures I have found. I cannot but think, however, that an error has slipped in in the measuring; the mentioned styli would also be uncommonly long and thin. Carter established the species as abyssicola vax. corticocancellala; it is, however, a very distinct species; Ridley and Dendy, in Chall. Monaxonida, also call the attention to the fact that it must surely be an independent species. The figures by Anna tier Hansen quoted above may surely be referred to this species. Locality: The Ingolf, station 143, 62° 58' Lat. N., f 09' Long. W., depth 388 fathoms (bottom temperature -f-o°4C); 6o° 19' Lat. N., 5° 39' Long. W., depth 620 fathoms (bottom temperature -^o°i5C) (Ad. Jensen, the cruise of the «Michael Sars>, 1902). Of the stations the former is situated a little to the north, the latter a little to the south, of the Faroe Islands. Geogr. distr. The specimen described by Carter from the « Porcupine has also been taken near the Faroe Islands, at 6o° 14' Lat. N., 6° 17' Long. W., depth 632 fathoms (bottom temperature -=- o°8 C). The species is thus only known with certainty from this limited locality. As mentioned above, it has also been taken by the Norwegian North-Atlantic Expedition; as among the enumerated stations one is also found situated north of the Faroe Islands, it may possibly have been taken there. The bathymetrical range is 38S— 632 fathoms, and the species is only known from the cold area. 6. C. oxeata n. sp. PI. I, Fig. 1. PL III, Fig. 10. PL XIII, Fig. 1 a— f. 1885. Cladorhiza abyssicola Armauer Hansen, The Norwegian North-Atlantic Exp. XIII, Spongiadae, partim, PL VII, Fig. 9. 1887. Cladorhiza abyssicola Fristedt, Vega Exp. vetensk. Iaktt. IV, 455. Irregularly dendritically branched from the base; the branchlets, especially on the principal axes, sometimes coalesced to more or less zving-shaped parts. The sponge attached below. The skeleton is of The Ingolf-Expedition VI. 2. 3 98 P0R1FERA. II. the common structure, in the principal axes it is enormously powerful. Spicula: Megasclera oxca o-jij — o'S'o"""; microsclera of three tonus, anisancorm unguiferm with five teeth, sometimes with six teeth in the larger end, 0-026 — o-oj./""", sigmata of two forms, large ones o-op — o- 12""", small ones, zuitk compressed terminal parts, o'Off—O'Ojj" , in m This species is more robust than the other Clador/iiza-species, and it seems also to be the one that may grow to the largest size. It may be described as a bush with few stems. To judge from a basal part in hand it is attached below to a hard substratum with an irregular base formed by more stems. From this base thicker stems arise, dividing immediately and continuing upward with irregular ramifications, growing thinner as they rise. From the principal stems and their ramifications thinner, often branched lateral branches issue again, but there is otherwise no definite difference between stems and lateral branches. In a couple of fragments in hand a tendency to a bilateral arrangement of the branches is seen in the outermost ramifications. Branchlets issue in the common way from stems and branches; they issue all round and are close-set, but they show no circular arrangement. They are broadest at the base, and are slightly conical outward. The stems and branches are less cylindrical than in the preceding species, as the branchlets are somewhat coalesced at their base, which is most frequently somewhat compressed, and branchlets that are placed above each other are then connected by low keels. In the stems this feature may be very prominent, so that the branchlets are arranged more or less in rows on keel-shaped parts, while the intervening parts are smooth without branchlets; by this means the stems get an angular or winged appearance. At the ends of the branches the branchlets often become short and close-set, and the ends of the branches are rounded and sometimes slightly swollen. The layer of tissue on the axes is down on the stems rather thin, but becomes thicker in the outer ramifications. The largest specimen in hand, which is broken both above and below and only consists of the skeleton, has a height of 26o mm and a breadth at the base of 30 mm , and divides here into two principal stems which immediately subdivide. The mentioned basal part, which consists below of several interwoven stems, has in this place a breadth of 50 mra . As before mentioned the stems taper evenly upwards in the ramifications. The branchlets have an average length of towards 5 mm , they are a little more robust than in the preceding species, and have in the middle a thickness of ca. 0'5 mm . The colour (in spirit) is yellow or yellowish white. The consistency is firm on account of the strong skeleton; but in the upper branchings the sponge is rather flexible, and the branchlets are very flexible. The layer of tissue coating the axes is soft and brittle. The surface is smooth, and slightly projecting spicules are found only at the ends of the branchlets. The outermost layer of the tissue is not differentiated as a distinct or removable dermal membrane. Oscula and pores were not observed. In one of the specimens in hand of this sponge worm-tubes and Bryozoa are sitting on branches that are denuded of tissue; as the other branches of the specimen are sound, the branches in question must accordingly have been denuded of the tissue while the sponge was living. The skeleton consists in the stems and branches of strong polyspicular fibres. These fibres compose by far the greatest part of the mass of the sponge, and attain an enormous thickness. At the lower end of the mentioned largest specimen, which is probably broken off a little above the base, the axis is 30""" thick, a little up on the thickest stem the thickness was measured to i8 mn \ and farther PORIFERA. II. 99 up on one of the branches it was still io mm . In the outermost ramifications the axes grow thinner, and are here i' nm thick or a little less. The fibres consist of closely united spicules, but they are not here all of them parallel to the longitudinal direction, a great part being arranged in other ways. If we regard a transverse section of a stem a rather marked stratification is seen; this stratification arises from the fact that layers in which the spicules are more or less parallel to the longitudinal direction, and which are, therefore, in the transverse section seen to be cut, alternate with layers in which the spicules are scattered but parallel to the surface. In the layers in which the spicules are placed in the longitudinal direction, they are to some degree arranged in bundles. The described con- struction of the axial skeleton is also distinctly seen in a longitudinal section. In the thinner branches no stratification is seen. The axes most frequently show a slight spiral twisting, which is, however, often very indistinct, or has quite disappeared, the spicules of the outer layer being scattered. In this species the axes are most frequently not cylindrical, but of an irregular contour, often with edges and keels; and irregular coalescings of various kinds may take place. The skeleton of the branchlets con- sists, as usually, of a fibre which is inserted in the axis and continues to the middle of the axis where most frequently several fibres meet. In this species these fibres have rather many spicules alongside; to be sure, they become a little thinner towards the point, but even there they consist of several spicules. The spicules of the part of these fibres that is inserted in the axis, are as usually spread in a fan-shaped way in the longitudinal direction; in the thinner branches the inserted part of the fibres of the branchlets is of about the length of a spicule, but in the thicker branches and stems also the branchlets continue to the middle, and then the part inserted in the axis gets a considerable length. In this case only the innermost part of the fibres of the branchlets, about to the length of one spicule, is spread in a fan-shaped way. It must also be supposed that the spicula-layers of the thicker axes mentioned before are layers of growth, and that the inserted fibres of the branchlets, with the exception of the innermost part, were at an earlier time outside the axis. In the layer of tissue out- side the axes some scattered spicules are found, some of which are situated just under the skin, partly between the branchlets, partly reaching a little into their basal parts. In the axes spongin is found cementing the spicules; it is most abundant downwards, and therefore the yellowish colour of the axes deepens downward, and at the base it becomes brownish. The axes have the common, somewhat hyaline appearance. Spicula: a. Mcgasclcra; these, as already indicated in the name of the species, are diactinal; the) 1 are typical oxea with equal ends, without any discernible tendency towards styli. They are straight or slightly, often a little irregularly, curved, or they have in the middle a sharp, but slight bend. From the middle they taper a little towards the ends, but the point itself is rather short, or at most of middle length; an especially marked off outermost point is often found. They have not rarely a swelling in the middle. These oxea, as mentioned, show no tendency to become styli; on the other hand, forms are found with one rounded end, but only singly; forms with both ends more or less rounded are, however, also seen, and I am, in both cases, most inclined to regard these forms as secondary or irregular ones. Between the needles in the axes and those in the branchlets the only difference is that the former are generally shorter and thicker than the latter; besides, needles with the mentioned sharp bend occur far more frequently in the tissue and branchlets than in the axes. IOO PORIFERA. II. When all sizes are included, the length is between 0-417 — o-8o mm , and the thickness is 0-014 — o-025 mm For the needles of the axes the length ma)- be given as being generally 0-417 — o-6 rem , and for the needles in tissue and branchlets ca. 0-55 — o-8o ram , and the thickness is rarely more than o-02i' nm . Some- times this difference is less marked, and it is especially found in the upper and outer ramifications, while down in the sponge and in the stems and the thicker branches it is more effaced. In the tissue fine, long pointed developmental forms are seen singly, b. Microsclcra; these are anisancorse unguiferse and sigmata of two forms, larger ones and smaller ones. 1. The an corse are of the common Clado- rhiza-iorm; they have a curved shaft and rather broad alae at the larger end. The}- have five teeth at either end, but forms with six teeth at the larger end are also found. The length varies from 0-026— o-034 mm , and the thickness of the shaft from 0-0028— o-oo35 mm . Developmental forms of the ancorae are found in small numbers. 2. The large sigma has a regular sigma-form; these sigmata are plane or almost plane; the length is 0-09 — o-i2 ,nm , in by far most cases nearest to the latter length, the thickness is 0-0057 — 0-007™™. Developmental forms in different stages were seen in no small numbers. These developmental forms are distinctly seen not to be cylindrical, but sharpened inward from a little over the middle and to the ends; this feature, on the other hand, is not to be seen in the fully developed sigmata. 3. The small sigma is only found in the end of the branches, and is of the same form, with inwardly sharpened terminal parts, as the sigma occurring in the same way in the preceding species. It is likewise contort, almost always a fourth part of a turning. The length is 0-047 — o-054 mm , and the thickness in the middle of the shaft about o-oo2 m:n . The ancorae and the large sigma occur partly throughout the tissue and partly in the dermal layer, especially the ancorae are abundantly present in the outermost layer of the branchlets. The small sigma only occurs in the point of the branches and not in all of them, but only in those that are distinctly swollen; here it is found abundantly. On the other hand, the large sigma is here only seen quite singly. Embryos. Embryos were also in this species found rather copiously in the tissue. They are roundish or most frequently oval, and they are surrounded by a thin membrane. Their size is about j mm By the examination they proved to be either without spicules, or only provided with develop- mental forms of the ancorae, but these were found rather copiously. The developmental forms were mostly rather young stages, they had a length of 0-024— °'° 2 7 mm i or about the same length as the ancorae of the grown sponge. The embryos are situated in the tissue outside the axes, they are fre- quently found at the base of the branchlets, or in this base itself; in a few cases they are seen out in the middle of the branchlets (Woodcut, Fig. 6). According to this I suppose that they leave the sponge by this way, and so we are again led to regard the branchlets as oscula. I have, however, not been able to find any canal, and accordingly, if such a one is found, it must be supposed to be closed. The fibre of the branchlet is almost always found in one side, and the canal must be supposed to run alongside of it. Also the embryo is placed in one side of the branchlet beside the fibre; it distends the branchlets in the middle, and on the sides where the fibre is not found, it is surrounded by a thin membrane only filled with microsclera. It is to be remembered, however, that the occurrence of the embryos in the branchlets may also be supposed to be owing to the fact that they develop here as in other places in the sponge. The figure presented by a branchlet with an embryo in it, involuntarily directs the thought PORIFERA. II. IOI to the figure given by Wyville Thomson, in The Depths of the Sea - 187, of Chondrocladia virgata. In this sponge all the brahchlets show a swelling in the middle mentioned by the author as a dark greenish oval mass of granular sponge matter;, a description that might very wel be used of an embryo situated in the branchlet. Wyville Thomson says that the branchlets end with a very narrow osculum. Carter also mentions the swelling, but has found no osculum; it may perhaps have been distinct, when the sponge in its fresh state was examined by Wyville Thomson, and have been closed later. If the mentioned swellings in the branchlets are owing to embryos, there is the curious peculiarity that an embryo is found in each branchlet. The quoted one of Armauer Hansen's figures of the exterior may with certainty be referred to this species; also one of the specimens of his C. abyssicola which I have examined proved to be the present species. Of the spicula-figures those on PI. IV, figs. 4 — 5 belong with some probability to this species. Also Fristedt's C. abyssicola proved, by my examining a fragment sent to me, to be the present species. Locality: Station 15, 66° 18' Lat. N., 25 29' Long. W., depth 330 fathoms (bottom temperature -=- o°75 C), station 143, 62 58' Lat. N., 7 09' Long. W., depth 388 fathoms (bottom temperature -HO°4C); further 65 57' Lat. N., 27 00' Long.W., depth 336 fathoms (bottom temperature 0°) (Wandel). The mentioned stations are situated in the Denmark Strait and north of the Faroe Islands. The species appears to be a native of the cold bottom, or the border of it. From station 3 with a bottom temperature of o°5 C. we have a fragment consisting of denuded skeletal parts. This fragment has surely been dead long, as a Suberitid, and other forms are growing on it, and it has moreover lost something of its original firmness. Therefore it must be supposed to have been removed from its native place. Geogr. distr. As mentioned the species has been taken bv the Norwegian North-Atlantic Expedition and in the Baffin Bay, depth 116— 215 fathoms (Fristedt I.e.). Fig. 6. Cladorhiza oxeaia n. sp. Branchlet with embryo. The fibre is running in the right side. X 20. ? The Clador/iisa-species are forms all of which are natives of rather deep or very deep water. The bathymetrical range of the genus is from 116 to 3000 fathoms. The genus is widely distributed, from ca. 8o° Lat N. to ca. 54 Lat. S. The arctic species live generally at considerably smaller depths than those of the Mediterranean and the Pacific. The species treated here, which represent all the arctic species, thus have a bathymetrical range from 116 to 1309 fathoms; with the exception of abyssicola they are all of them natives of cold water. The species from the Atlantic and the Pacific have a bathymetrical range from 700 — 3000 fathoms; with regard to these species the bottom tempera- ture of the localities at which they have been obtained varies from ca. o° to 4°4 C. (32° 1 — 40 Fahren- heit). The bottom temperature o : C. (32°i Fahrenheit) applies to the southernmost species C. moniliformis R. and D. obtained at 53 55' Lat. S., 138 35' Long. E. at a depth of 1950 fathoms. 102 PORIFERA. II The Cladorhiza-species described at present are the following ones: 1872. C. abyssicola O. Sars. 1876. - corticocancellata Cart, (as a variety of abyssicola). 1887. - abyssicola var. rectangularis R. and D. The Pacific. 1887. - - linearis R. and D. The southern Pacific. 1887. - moniliformis R. and D. Southwest of Australia. 1887. - longipinna R. and D. The northern Pacific. 1887. - similis R. and D. The southern Pacific. 1887. - tridentata R. and D. Between Prince Edward Island and Crozet Island. 1887. - pentacrinus Dendy. Northeast of New Zealand. 1902. - flos abyssi Tops. Off the Cape Verde Islands. - gelida mihi. - tenuisigma mihi. - iniquidentata mihi. - oxeata mihi. The two varieties rectangular is and linearis established by Ridley and Dendy are surely independent species. In Zool. Anzeig. XIX. 532, Kieschnick has established a species C. depressa. As it is from a littoral locality it is scarcely a Cladorhiza, and as Thiele, in his account of Kieschnick's species (Abhandl. Senckenberg. Nat. Gesell. XXV, 1903) has been unable to find anything whatever that might correspond to it, the species must be regarded as non-existing. With regard to the Asbcslopluma-speties described under the generic name of Cladorhiza see under the genus Asbcstopluma. Chondrocladia Wyv. Thomson. Erect, branched in different ways; often a central axis wit// lateral brandies which may be papillose, or the branches gathered at the top ; sometimes branched like a tree, or finally of a more irregular form. The skeleton is in close accordance with the form, and consists in the axis or axes of poivcrful spicnla-fibrcs, and of similar, but thinner ones in the branches. Spongin is found in the fibres. Spicula: Megasclera styli, and sometimes finely spinulous styli in a special layer coating the stalk: microsclera: the characteristic viicrosclcra are isancora 1 unguiferce of one, two. or three sizes with from three to nine teeth at either end. to which forms sigmata are (always) joined. 1. C. gigantea Arm. Hans. PI. IV, Fig. 1. PI. XIII, Fig. 2 a— 1. 1880? Cladorhiza graudis Verrill, Proceed, of the U. S. Nat. Mus. II, 1879, 2 °4- 1885. Dcs?nacidon clavatum Armauer Hansen, The Norwegian North-Atlantic Exp. XIII, Spongiadae, 14, PI. II, fig. n. PORIKKRA. II. 103 1885. Desmacidon nucleus Armauer Hansen, ibid. PI. Ill, fig. 1, PL VI, fig. 17. 1885. Desmacidon gigantcum Armauer Hansen, ibid. PL II, figs. 12, 13, PL VII, fig. 8. 1885. Desmacidon arcticum Armauer Hansen, ibid. 15, PL VI, fig. 16. 1887. Cladorhisa nobilis Fristedt, Vega-Exp. vetensk. Iakttag. IV, 456, PL 25, figs. 60—65, PI- 3 1 ) &g- 2 ^>- Erect, club-shaped, on the upper part with a number of short, papillose branches swollen towards the point: below the axis is dissolved to a branched root. A layer coating the stalk and root and pro- vided with special spicules present. The skeleton af the generic type, consisting of a powerful, below spirally twisted spicula-axis through the middle of the sponge, and thin spicula-axes in the papilla. Spicu/a: Megasclera styli of two sizes, long ones in the axes, 1-2—2""", shorter ones in the other parts of the body 0-36 — 7-2"""; finely spinulous styli in the layer coating the stalk ir/rS'—o-jp"'"; microsclera of three forms, isancorce unguiferce of two forms, large ones with six teeth 0-037— 0-077""", small ones with six to nine teeth croiS — o-oj""". sigmata with compressed terminal parts 0-037 — 0-043""". This beautiful and interesting species reaches a considerable size, as has already been expressed by Armauer Hansen in the specific name, although his specimen had only half the length of the largest specimen before me. The species consists of a stem, dividing below, first into rather thick branches, then by and by into thinner ones, so that a rather richly branched root is formed. The stem continues upwards, and increases in thickness in its upper half, so that the sponge becomes about club-shaped. The upper, thicker part is set with a great number of papillae, not regularly arranged. The papillae have a broadly conical base passing into a thinner stalk which again ends in a more or less swollen head. The papillae may otherwise be somewhat different in length and form, the length of the stalk may be different, and the end may have a more or less marked head-like swelling. The papillae may also be somewhat differently directed; in the specimens in hand most of them are more or less turned downwards, only the uppermost ones are directed upwards. Up to where the lowermost papillae begin, the root and stalk is coated with a layer provided with special spicules and of the same character as that found in several Asbcstopluma-species; the layer is here very thin, and it is highly filled with mud, so that it must be supposed that the sponge has been sunk in the bottom so far as the layer reaches. The largest specimen in hand has a height of 43 cm , of which the stalk and root make about the half part; the stalk is ca. 2i mm thick, and the greatest thickness above is 55""". The length of the papillae inclusive of the conical base cannot be given exactly, but it does not exceed 25"™, and in their thinnest stalk-shaped part they have a thickness of 3 — 5 mm . Armauer Hansen's specimen was 22 cm high, and two smaller specimens before me are ca. i5 cm high, the other measures being in proportion to this. The colour (in spirit) is yellowish white; the lower part, which is covered by the coating layer, is, on account of the mud in it, dark gray, which colour ceases with a sharp boundary line. On account of the axial skeleton the sponge is firm and stiff, and the layer has outermost a rather hard, crusty consistency, but it is inelastic and somewhat brittle. The outer crusty tissue is not sharply bounded inward, but passes more or less evenly into the inner, softer tissue. The surface is apparently smooth, but under a magnifying glass it is seen to be finely shaggy. The outer crusty layer may rather easily be peeled off, while the outermost membrane, the dermal membrane proper, may be distinguished, but cannot, or only with difficulty, be isolated. Pores may be I04 PORIFERA. II. seen in the dermal membrane, and were measured to a size of ca. o'oa""". They are only observed with difficulty, the outer layer of tissue having the character of very small subdermal cavities situated within each other and separated by membranes, and the pores piercing only the very outermost mem- brane. From the subdermal cavities cylindric canals continue inward which canals may be observed, when a piece cut off parallel to the surface is regarded from the inside. Oscula: Separate great oscular apertures are not to be found, but it is likely that the papillae carry the excurrent openings, as the inner tissue between the central axis and the outer layer is lacunous, and canals are running longitudinally in the papillae, partly in the tissue between the axis and the outer layer, partly as sharply and distinctly bounded canals in the outer layer. Outermost in the terminal part of the papilla a cavity is found, or the middle part of the head of the papilla consists of a somewhat lacunous tissue without spicules. Now the end of the papilla is copiously provided with poreshaped openings, and as I suppose the said canals, at all events those running in the inner tissue, to be excurrent canals, I suppose the openings in the terminal part of the papilla to be excurrent ones. The skeleton consists of a strong axis running through the middle of the sponge, and also continuing into the branches of the root. The axis is not quite compact, but is composed of a number of close-lying, strong fibres. In its lower part the axis is spirally twisted; this twisting is here very distinct to the naked eye, as it is not the spicules of the single fibres which are spirally arranged, but it is the whole, of fibres composed stalk that is twisted, so that it gets some resemblance to a rope. In the single fibres, on the contrary, the spicules are placed in the longitudinal direction of the fibres without any twisting. The twisting is most marked in the lower part of the stalk, but upward it becomes less marked, and at last it is lost; it disappears also in the root-branches. In the largest specimen the thickness of the spicula-axis is ca. i4 ,nm . Through the middle of each papilla runs a fibre, which is formed by one of the fibres composing the axis bending off and passing through the papilla. Where the fibre bends off from the stem it is supported by some spicules placed in the angle and reaching to the middle of the stem. The papillae evidently correspond to the branches of the Clado- /■///iff-species. The skeleton of the other parts of the sponge supports the layer of tissue that coats the axis and its branches, i. e the papillae. In the crusty outer layer this skeleton consists of a very dense layer of needles lying irregularly in all directions. Part of the spicules project through the surface and makes it shaggy. Down on the stalk the la)er of tissue consists only of this outer, firm part, and it is easily separated from the stalk. In the thicker part of the body, on the other hand, the crusty layer passes inwardly, with a more or less indistinct bordering, into the soft, more lacunous layer of tissue nearest the axis which layer is provided with fewer spicules, partly scattered, partly gathered in bundles or shorter fibres. Also here the whole layer may be easily separated from the axis. Down on the stalk the crusty layer is about 2 mm thick, higher up in the expanded part it reaches a thickness of 3— 5 mm . In the papillae the construction of the skeleton is the same; in a transverse or longi- tudinal section the fibre is seen in the middle, then a soft layer with fewer spicules, and outermost the crusty layer (Woodcut fig. 7). The soft tissue between the crust and the fibre is here rather thin. The fibre continues to the point of the papilla, where it ends at the outer end of the cavity there; it has an average thickness of about i ram . The coating layer of the stalk and root is thin, and does not exceed i mm in thickness. It is of a character somewhat different from what it is in the Asbesfophii>ia-s\>A'""", fo.xa with spiued ends o-oj — o m j2 ~,mm This species, which in its exterior form reminds somewhat of a Suberites, is formed as a more or less high cushion, and has a roundish, more or less oblong contour. One specimen in hand is rather high in proportion to its size, and therefore somewhat irregularly cylindrical. The sponge seems always to grow on a firm underlayer, and we have specimens growing on stones, on Brachiopoda, on shells of muscles and snails, and on Hornera lichenoides. The largest specimen, which is longish, is 55 mm long and about 25""" high ; other more roundish specimens are of a similar or smaller size, but often of the same height, so that they become more globular. The smallest specimen has at the base an extent of n""" and is ca. 8 mm high; the mentioned, somewhat cylindrical specimen has a breadth of i2 mm and a height of iy mm . The consistency is firm, about as in Suberites. The colour (in spirit) is yellowish white to gray. The surface is very finely and densely shaggy, almost velvety, from pro- jecting spicules. Seen under a magnifying glass the surface presents a finely reticulate appearance on account of the many small close-set subdermal cavities, which shine through and are separated by the projecting spicula-bundles. The dermal membrane is a thin film; it has no special skeleton, but is supported by the close-standing spicula-bundles, which are spread in a somewhat penicillate way and it is pierced by these bundles. It is not, therefore, to be separated by itself. Oscula are circular or somewhat irregular openings surrounded by a more or less projecting, spout-shaped margin formed by the skin. It is not, however, the thin film that has been designated as dermal membrane, which forms this spout by itself alone, but the skin is here thicker, and the fibres supporting the dermal membrane bend into the oscular rim and form a close spiculation of parallel spicules, all with their point towards the oscular aperture. The greatest oscular diameter may be 3 mm ; the oscula are generally found about at the top or middle of the sponge in a number of ca. three to seven, but besides these some, often smaller ones, are frequently found scattered round on the sponge; sometimes also a few groups of oscula may be found; in one of the largest individuals thus eleven oscula are found altogether; on the smallest specimen only one osculum is found. The pores are found in the areas of the skin; they are circular and small; they were measured to a diameter of 0-017 — o - 048 mm . The skeleton. In the inner part of the sponge the skeleton has an irregular, somewhat hali- II2 PORIFERA. II. chondroid structure; some polyspicular fibres are found, running without any regularity, and otherwise the tissue is filled with irregularly scattered spicules. At a little distance from the surface the skeleton by degrees gets a different character, fibres occurring here that run more or less perpendicularly to the surface; in their outer part these fibres divide, and the outermost fibres formed in that way pierce the surface in bundles spread in a somewhat penicillate way, and support the skin like pillars. Below the skin, therefore, is found a great number of small subdermal cavities, or more exactly, one large such cavitv. The height of the pillars, which is the same as that of the subdermal cavity, is on an average o - 4 mm . Between the fibres no transversal fibres or transversal spicules are found. The men- tioned pillars are by no means always perpendicular on the surface; they may be placed more or less obliquely on it, and thus be somewhat recumbent. When the surface of the sponge is seen under a magnifying glass, this fact is distinctly seen, as also, that in one part of the sponge the pillars are all directed to one side, in another part to another side, and in other places again they are directed per- pendicularlv upward; by this means a certain configuration of the many small areas in the skin may appear, only, however, to be seen by means of a magnifying glass. The outermost spicula-bundles of the pillars, which pierce the dermal membrane, consist entirely or to some degree of spicules shorter and thicker than the other spicules of the skeleton. These dermal spicules may occur somewhat differently in different individuals. In some individuals the projecting spicula-bundles consist almost exclusively of these shorter needles, in others, on the other hand, they are found in smaller numbers, and many of the long spicules are found in the projecting bundles. According to this it would seem, as if in this feature some difference was found between different individuals. If, however, thin sections perpendicular on the surface are examined, the fact seems to be that when an abundance of the long spicules is found in the projecting bundles, many of the shorter dermal spicules are also found, and the bundles are larger, while they are smaller, when consisting almost exclusively of dermal spicules. It may be possible, therefore, that the mentioned difference is owing to a contraction, by which the dermal spicides are drawn back between the spicules inside. With this view agrees the fact that those of the specimens in hand in which the dermal spicules are less prominent and mingled with the longer ones, are low and very densely shaggy, while the higher individuals are less densely shaggy, and in them the projecting bundles consist almost entirely of dermal spicules. Vosmaer says 1. c. : The spicules are kept together by a very slightly developed keratode or pseudokeratode ; I have not been able to find spongin in the skeleton, and I suppose that none is present. Spicula: a. Mcgasclera are subtylostyli ; they are divided into two forms, not, however, sharply separated from each other; one form, as before mentioned, forms the whole skeleton and is also found, in larger or smaller numbers, between the spicules piercing the dermal membrane; the other form, more or less mingled with the preceding one, forms these projecting spicula-bundles. The skeletal spicules proper are slender, straight, or slightly, somewhat irregularly curved; they taper evenly to a long point that may be a little shorter pointed at the extremity. The opposite end is slightly swollen to a head passing evenly, without any marking, into the shaft of the needle. They are quite slightly fusiform, being a little thinner below the head-end than in the middle. The length varies from about 0-45— o-65 n,m , and the thickness is 0-006— cooa/"" 1 . The shorter and thicker spicules in the projecting bundles are somewhat fusiform, being thickest in the middle, and the point is not so long. Their PORIFERA. II. 113 length is generally 0-29 — 0-4""", but, as before mentioned, transitions to the skeletal spicules are found, especially among the spicules that are placed immediately below the dermal bundles. The thickness is 0-009 — 0'0i8 mm , but in some individuals it does not exceed o-oi4 m "\ Of the skeletal spicules devel- opmental forms were seen, down to quite fine ones, but in very small numbers, b. Microsclera ; these are of two forms, isochelse palmatce and toxa with spined ends. 1. The chela? are of the common form; their shaft is about straight or quite slightly curved, the middle part between the two terminal parts is straight or a. little curved inward; the length of this middle part is generally some- what less than one third of the whole length. The tooth is about as long and broad as the alse. The chelse vary somewhat as to size, and this may again to some degree influence the dimensions of the different parts. The length is 0-007 — o-oi28 mm , most frequently near the latter size; the breadth is ca. o-oo2 mm . Developmental forms were seen singly as quite thin, recurved staves. 2. Toxa. The general form of these is one that has in the middle a strong curve while the ends are evenly curved to the opposite side, and their outer part is most frequently straight. They are generally more or less twisted in the middle, and most so, it would seem, in the smallest bows. From the mentioned and by far most common form they ma)- vary in different ways, especially so, that the curve in the middle becomes more open and the legs more straight, so that we may get a bow with a very great angle and only one curve. The outer ends of the bow are spined for a quite short way; the spinosity mav be a little varying, but generally there are comparatively few, rather coarse spines. These bows are exceedinglv varying as to size; thus the length, which is somewhat dependent on the curve, varies from o-07 mm quite up to o-32 ram ; the thickness, which is the same through almost the whole length of the bow, varies in proportion to the size from about o-ooi — o-oo4 mm . All these sizes must be regarded as fully developed bows; neither would the small ones by a continued apposition grow to the form of the large ones, and they have likewise all, also the smallest ones, spined ends. On the other hand small bows occur, thinner than the fully developed ones of the same size, and almost not at all spined, or only with small spines; these, no doubt, are developmental forms. Thus the spines are not found from the beginning, but only formed by and by. Of the microsclera the chelse are found in exceedingly large numbers both in the dermal membrane and throughout the tissue, the bows are found in the tissue in somewhat smaller numbers. As I have examined the type-specimen described by Schmidt I.e., I have been able with certainty to establish the specific identity between Schmidt's Suberites arciger and Vosmaer's Arte- iii is in a suberitoides. Already Fristedt 1. c. draws the attention to the probability of the identity. It may easily be understood that Schmidt has overlooked the chelae, as they are exceedingly small, their smallest size being perhaps the smallest chelae occurring at all. Schmidt further states that besides the common needles a form occurs which variirt von der Kugelform bis zur Gestalt einer kurzen, an beiden Enden stumpfen Nadeb, and he figures two such bodies; this fact, together with the chelae, has for Vosmaer been the reason why he has not united the two species. The bodies mentioned by Schmidt are, however, only monstrosities of the kind that is upon the whole not rarely found in sponges. It seems especially to be the dermal spicules, which are sometimes trans- formed in a monstrous manner. Locality: Station 28, 65 14' Lat. N., 55 42' Long. W., depth 420 fathoms; Station 127, 66° 33' The Ingolf-Expedition. VI. 2. 15 ii 4 PORIFERA. II. Lat. N., 20° 05' Long. W., depth 44 fathoms; Greenland, Proven (Bolbroe, Schmidt's type specimen); the Davis Strait 65 27' Lat. N., 54 45' Long. W. (Wandel); East-Greenland (the East-Greenland Ex- pedition 1891—92); Forsblad's Fjord, depth 50 — 90 fathoms, Hurry Inlet depth 50 fathoms (the Amdrup Expedition 1900); twenty miles east of Seydisfjord, depth 135 fathoms (Wandel); 64 27' Lat. N., 13 27' Long. W., depth 84 fathoms, 64° 58' Lat. N., n° 12' Long. W., depth 300 fathoms (Ad. Jensen, the crnise of the Michael Sars 1902). The mentioned localities are situated in the Davis Strait, off East- Greenland, North and East of Iceland, and between the Faroe Islands and Iceland. Geogr. distr. Besides at the localities mentioned above, the species has been taken between Norway and Spitzbergen, 72 36-5' Lat. N., 24 57-5' Long. E., depth 140 fathoms ( Willem Barents ); Spitzbergen, depth 40 fathoms, Kola Bay depth 95 — 100 fathoms (Fristedt); Nova Scotia, 43° 03' Lat. N., 63 39' Long. W., depth 85 fathoms (Challenger). Thus the species is exclusively a northern one, its southernmost boundary being 43 03' Lat. N., and, as usual, it goes only so far south at the eastern coast of America. Its longitudinal distribution is from the Davis Strait to Spitzbergen. It has been taken at depths from 40 fathoms (Spitzbergen) to 420 fathoms (the Davis Strait, 65 14' Lat. N.). 2. A. apollinis Ridley and Dendy. PI. XIII, Fig. 4 a— g. 1887. Amphilectus apollinis Ridley and Dendy, Challenger Report, Monaxonida, XX, 124, PI. XIX, figs- 3> 3 a — c - Formed as a thick incrustation or flat cushion. The dermal membrane a thin fllm with a reti- culation of spicules. The skeleton a halichondroid reticulation of polyspicular fibres, spicula- bundles and single spicules. Spicula : Megasclera styli of tzuo forms, larger ones, smooth, or with a slight erenulatiou at the head-end, o'jjj — o-8""". in the main skeleton ; smaller ones, with very slightly spined head-end, o-2g — o-jg""", in the dermal skeleton; microsclera of two forms, small isochehv palmatce o-o/j—o-o/8""", toxa, large, spined ones o'jo""", smaller, smooth ones 0-085 — o-26'""". Of this species we have only two fragments with a greatest extent of 35""". Ridley and Dendy describe their species as «massive, amorphous, cavernous. The largest specimen is oval, cake-shaped; about 50 mm long by 38 mm wide and ig mm thick . The fragments in hand agree entirely with this description and convey also the impression of having belonged to a flat, thick crust-shaped sponge. The colour (in spirit) is light yellowish gray. The consistency is loose and soft. As the fragments in hand are much damaged, the original surface has only been preserved to a slight degree; I take it, however, to be certain that it is sparingly shaggy from projecting spicules. The dermal mem- brane is a thin film pierced by the mentioned spicules, and it seems to be provided with a somewhat irregular reticulation of styli of the smaller form. Of pores a few were seen in the undamaged parts of the dermal membrane; oscula, on the contrary, were not found. Ridley and Dendy describe the dermal membrane in a similar way, nor have they seen any oscula. The skeleton is an irregular and somewhat halichondroid reticulation of polyspicular, but loose and little marked fibres, spicula-bundles, and scattered spicules. In the nodes a very distinct, clear, and white mass of spongin is found. PORIFERA. II. 115 Spicula: a. Megasclera are styli of two forms, larger ones forming- the skeleton, and smaller ones forming the dermal reticulation. The skeletal styli are more or less curved, often a little irregularly, the curve is generally found nearest to the rounded end; the opposite end tapers to a point of middle length the outer end of which may be a little shorter pointed. The upper end of the styli is either quite smooth, or the}' have, on the very uppermost surface only, a few exceedingly small spines appearing as a slight creuulation. The length varies from 0-53 — o-8 mm , and the thickness is 0-013 — o-020 mm ; the longest ones are far from being always the thickest ones; finer developmental forms occur, but in small numbers. The dermal styli are straight, the head-end is often quite slightly swollen, so that they approach subtylostyli, but they cannot, however, be designated as such; the opposite end tapers more or less, but always rather little, and therefore the point is short. The most particular fact about them is that the head-end is gener- ally or always slightly spined; some difference may be found in the spinosity, but it is only the very uppermost part that is provided with more or fewer slight spines. The length of these needles is between 0-29 and 0-39™'", the thickness is 0-005 — o - oo8 mm ; the shortest ones are often the thickest ones. b. Microsclera. These are of two forms, isochelse palmatce and toxa. 1. The isochelse are of a quite similar form as those of the preceding species; the shaft is quite slightly curved, the middle part, making about one third, is straight, the tooth is a little narrower but of the same length as the alse, the tuberculum is rather long and most distinctly conspicuous in its lower end. The length of the chela is 0-014 — o-oi8 mm , and the breadth about ooo4 mm . 2. Toxa; the largest of the bows have a similar form as in the preceding species, only the spinosity is, perhaps, a little finer, and it reaches a little farther up the legs, and the outer part of the legs is generally not straight. The bows have a length of up to o\40 mm with a thickness of o-oo4 mm . Of the bows thinner forms with slighter spinosity mav be found, but I have seen no younger developmental forms. There is almost no variation in the form of these bows. On the other hand smaller and finer bows occur in rather large numbers; some of them are of a similar form, but the greater part have a considerably flatter curve; and rather fre- quently a form is seen having a rather strong bend in the middle, but a little way from the bend their legs turn horizontally and become straight or almost straight. The length of these bows was measured to 0-085 — o-28 mm , and the thickness is in proportion from exceedingly fine, ca. o-ooo7 ,nm , to o-0O2 mm . None of all these bows are spined; to judge from their form, they do not appear to be devel- opmental forms of the bows before mentioned; the largest of them, which are of a similar form as the preceding ones, may, however, be developmental forms of these. All the bows are frequently some- what twisted. Of the bows a few specimens were seen of a quite colossal size, viz. 0"56 mm long, and o-oi4 mm thick. These bows had no spines or only a few quite rudimentary ones. The question is here evidently of monstrous forms arisen by a continued, abnormal silicious deposition, and by this continued depo- sition the thorns have by and by become effaced. The same feature may be found in other forms; thus in Clador/ifza-species I have found abnormal silicious deposition in the ancorse, so that they became exceedingly thick, and the teeth were partly or almost entirely effaced. Of the microsclera the chelae occur very abundantly both in the dermal membrane and in the body itself; the bows are not numerous, and were not seen in the dermal membrane. Remarks: On account of the localities from which Ridley and Dendy and I have the species, 15* I: 6 PORIFERA. II. respectively East-Greenland and Kergnelen, some suspicions might be aroused with regard to the certainty of the identification. I have had, however, a fragment of the type specimen for examination, and I regard the identification as quite sure. First also the type specimen shows that a slight crenu- lation of the upper end of the skeletal styli is most frequently found. Next the type specimen, besides the spined bows, has also smooth ones, as mentioned in my description. Ridley and Dendy do not mention any smooth bows; but when giving the size of the bows they say: size of full-grown spicules, accordingly they must have seen some bodies which they have taken to be younger forms, and these bodies have, no doubt, been the smooth bows. A little difference is found between the type specimen and my specimen, but it is only a slight difference of size in the spicules, which is of no importance and would, no doubt, be effaced, if a richer material was at hand. Thus the styli of the type specimen do not exceed 0'536 mm , and this is about the lower limit for the styli of my specimen; and the toxa attain only a length of o i 3 mm , while in my specimen they may be o-4 mm long; also the dermal styli are upon the whole a little smaller, whereas the chelae are of equal size. Locality: East-Greenland, the depth not stated (The East-Greenland Expedition 1891—92). Two fragments. Geogr. distr. The species was before only known from Kerguelen, depth 20—60 fathoms (Chal- lenger). The distribution of the species is accordingly very peculiar, as it seems to be bipolar; it is, however, to be remembered that we have hitherto so slight a material of this species, only two speci- mens having been obtained by the Challenger Expedition. The genus Artemisina was established in 1885 by Vosmaer with the species subcritoidcs, which has now proved to be identical with the Suberites arciger established by O. Schmidt in 1870. When the quite heterogenous genus Aviphilcctus is dissolved, the species apollinis established under this genus by Ridley and Dendy in 1887 must be referred to the genus Artemisina, as has been done by Tops en t. Then in 1892 Topsent has established a third species, A. transiens, and in 1904 a fourth species, A. erccta. A fifth Artemisina-species seems to be found in the Desmacidon rimosa established by Ridley (Zool. Collec. of the Alert?, 609, PI. LIU, fig. F., PI. LIV, fig. mm); it is provided with larger and smaller styli, the latter often with spined head-end, and it has of microsclera small isochela; palmatse and smooth bows. Thus at present these five species make up the genus. By the establishing of the genus some stress was laid upon the suberites-like consistency; this character, how- ever, is not found in the species apolliiiis and erecta, whose consistency is different from that of the other species. With regard to the spiculatiou the species agree in having small palmate isochelse and toxa. In the megascleres, 011 the other hand, some difference is found; thus arcigera has subtylostyli, of which those piercing the dermal membrane are of a special form, apolliiiis, erccta, and rimosa have styli and as dermal spicules a special form of styli with slightly spined head-end 1 ), transiens finally has only one form of styli, all with spined head-ends. Of bows arcigera and erecta have spined bows, 1) The description of the distribution of the two forms of styli in rimosa is somewhat obscure, but it is at all event stated that the small ones occur in the dermis. PORIFERA. II. 117 transiens and rimosa smooth ones, and in apollinis both kinds seem to be found. Therefore it is perhaps doubtful whether the genus in future will prove to be a natural one; but at present it must be maintained. If it were to be dissolved, the species, on account of their spiculation, might best be referred to Esperiopsis, in which genus we have already species with the same combination of microscleres, but not, however, with spined bows. - - What is also to be noticed is the great resem- blance with regard to spiculation which most species of the genus show with Hymeraphia and Rha- phidophlus, of which genera styli, dermal styli with slightly spined head-end, isochelae palmatae of nuite the same form as in Artemisina, and toxa are characteristic. Homoeodictya Ehlers (emend.). The form very varying, from thick incrustations through more massive sponges to erect ones of various forms, sometimes plate-shaped, or digitately branched of a Chalina-like appearance. The skeleton also very variously developed, diffuse, irregularly polyspicular, or forming a regular reticulation with pri- mary fibres bending towards the surface in a fan-shaped way, and secondary fibres. Spongin present in varying degree, sometimes, in the most Chalina-like species, in rather great amount, forming sheaths round the fibres. Spicula: J/egasclera diactiual, oxea or strougyla ; microsclera isochehe palmata 1 or arcuatir, to which may be added rhaphides (and perhaps sigmata). Ehlers, who recognized that Bowerbank's genus Isodictya, in which the species palmata was found, was too heterogeneous, established for palmata the genus Honuvodictya (Die Esperschen Spong. Program zum Eintritt in dem Senat , Erlangen 1870, 17 et 32), attaching special importance to the equi-ended chelae 1 ). On the other hand he laid no stress on the special form of the chela, which he described, however, in the specific description. Ridley and Dendy, in Challeug. Report, regard Ilomasodictya as a subgenus of Desmacidon, but they use as a diagnostic character the peculiar bending in of the axis in the chela, and they refer to the subgenus only three species all of which show this character. As mentioned in the introduction, such genera containing species with ancorae and species with chelae must be divided, and this is exactly the case with the genus Desmacidon. The species of this genus must be divided in two groups, one with aucorae, the other with chelae. As the type of the genus Desmacidon, D.fruticosus Bow. has ancorae, the generic name of Desmacidon must be kept for the species with ancorae. The question might then be of forming a new genus for the other group. I think, however, that it will be more correct, at all events at present, not to under- stand Hoviosodictya in the restricted sense in which it was understood by Ridley and Dendy, but to enlarge it to comprise all species of the old genus Desmacidon with chelae. I think that these species are naturally connected; to be sure there is, as shown by the diagnosis, some difference as to form and skeletal structure, but the species seem here, as in several other genera, to form a continuous series; H. conulosa R. and D. occupies, as already stated by the authors, an intermediate position. As to the microsclera, the genus will comprise forms with arcuate chelae, with common palmate chelae, ') Ridley and Dendy say that Ehlers established the genus without giving any diagnosis; this, however, is not the case, as Ehlers, on p. 32, gives a diagnosis of the genus rather good for its time. XI 8 PORIFERA. II. and with the peculiar palmate chelae that were characteristic of Homceodictya in the sense of Ridley and Dendy. Thus the genus is divided in three groups, which groups, however, can scarcely be of generic importance, as arcuate and palmate chela; may occur in the same species (for inst. Espcri- opsis forcipula Ldbk.), and the peculiarity of the Honioodictya-c\\e\a. is also found elsewhere, for instance in several Espcriopsis-species (see p. 15). At present it is not possible to decide, which of the described species are to be referred to Desmacidon, and which to Homosodictya. The case is that when no figures are given, it cannot be seen from the commonly used expression ctridentate isochelae whether the question is of arcuate chelat- or ancorse; and even if figures are given, they must be good ones to give sure information. I shall here therefore only enumerate some species, which with certainty belong to Homa-odictya : Microsclera. H. palmata Johnst Homceodictya-chelae. 1885. - (Myxilla) flabclliformis Arm. Hans Chelae arcuatae. 1887. - (Desmacidon) conulosa R. and D Chela; palmatae. 1887. - ( — ) ra/uosa R. and D Chelae arcuatae. 1887. - kerguelenensis R. and D Homceodictya-chelse. 1887. - grandis R. and D Homceodictya-chelae. 1889. - (Fibularia) raphidifera Tops Chelae arcuatae, rhaphides. 1903. - (Desmacidon) setifera Tops Cheke palmatee. 1904. - ( ) peltata Tops Chelae arcuata;, rhaphides. None of these species have sigmata, and it may be doubtful, whether such are found in the genus. 1. H. flabelliformis Arm. Hans. PI. IV, Figs. 2— 3. PI. XIII, Fig. 5 a— e. 1885. Myxilla flabelliformis Armauer Hansen, The Norwegian North-Atlantic Exp. XIII, Spongiadae, 12, PI. II, fig. 14, PI. VI, fig. 6. 1903. Desmacidon clavellata Arnesen, Bergens Mus. Aarsberet. 1903, Nr. 1, 13, Taf. II, Fig. 2, Taf. IV, Fig. 4. Erect, stalked, broadly leaf-shaped (grown specimens) or chib-shaped (young specimens). Tin- dermal membrane a thin film with scattered spicules. The skeleton consists of polyspicular primary fibres passing from the stalk into the leaf and bending in a sheaf-like way to all sides towards the sur- face; they are connected by transverse spicules most frequently placed singly. Spicula: Megasclera oxea of two sizes, large ones in the skeleton. 0-41— 0-55""", smaller ones in the skin. 0-268— o-jj"""; micro- sclera chela arcuata-. highly curved, o-ojo — 0-04""". Of this species we have two larger, somewhat damaged specimens, and two small ones. The species has below a stalk attached by a somewhat expanded basal part, but the specimens in hand are torn off, with the exception of the smallest one, which is attached to a stone. Arnesen 1. c. PORIFKRA. II. 119 says that it sits on serpula-tubes, muscles, stones etc. The stalk passes into a rather thick, more or less fan-shaped leaf; this leaf is thickest in the middle, but becomes thinner towards the edge. The largest specimen has a height of ca. o,o mm , and the leaf has a similar breadth. The greatest thickness of the leaf in the middle is ca. ij mm , the stalk has a height of 20" ,m and a thickness of fully io mm . The other specimen is a little smaller, and the leaf especially is less broad. Of the small specimens one has a height of 24 mm , half of which is a stalk scarcely 2 mm thick; this specimen may more properly be called club-shaped than leaf-shaped, its upper part having a breadth of o, mm and a thickness of 6 mm . The smallest specimen is only i2 mm high, of which the stalk makes about the half. This specimen is quite club-shaped and has a greatest breadth of 3 mni . The consistency is rather loose, but the stalk is considerably harder. The colour (in spirit) may be given as light brownish gray. Of the surface I dare, on account of the condition of the specimens, say nothing with certainty, but doubtless the ends of the fibres project making it sparingly shaggy. The dermal membrane^ to judge from the few places of the sponge where it is kept, is a thin film provided with scattered oxea and with very close-lying chelae. Oscula and pores I have not been able to observe on my specimens, but on a young club-shaped specimen, kindly sent me by Miss E. Arnesen, an osculum was found at the top, as has been figured by the authoress 1. c. Rather close-standing canals run through the sponge continuing from the surface horizontally inward or somewhat downward; these canals convey an impression of being larger on one side than on the other, and perhaps therefore, in the grown, leaf-shaped sponge pores and oscula have been localized each on their side of the sponge. The skeleton consists in the stalk of close-lying, strong, polyspicular fibres connected by power- ful spicula-bundles, so that a solid network is formed. This skeleton forms the greater part of the stalk, only a little network of thinner fibres being found on the outside. From the stalk the fibres continue into the leaf and bend to the sides in a fan-shaped way, branching and by degrees becoming thinner; thus the outer branchings form the edge of the sponge. The fibres, however, bend also and ramify in a fan-shaped manner towards the two surfaces of the sponge, where accordingly their outer ends projects everywhere. Thus these primary fibres have a rather regular course, and the distance between them is also rather equal, ca. 0-29— cr4 m,D . The fibres are thickest in the middle of the sponge and may here reach a thickness of o-2 mn '; then they consist of many spicules alongside, but through their outward course they become thinner and go down to a thickness of only a few spicules, in a few- places even they consist of only two spicules alongside. In the stalk the fibres may reach a thickness of o-27 mm . The primary fibres are connected by transverse spicules most frequently single, only some- times two or three together; the transverse spicules are placed perpendicularly on the primary fibres, but otherwise without regular intervals, they do not form continuous fibres. In the skeleton a distinct but clear and white mass of spongin is found, especially distinct in the nodes. It may in some places be rather copious and entirely coat the fibres, but this does not seem to be the common case. In the stalk it is more copious, here it coats the fibres entirely, and is of a yellowish colour. Spicula: a. Megasclera are oxea, divided in two rather distinctly separated sizes, of which the larger ones form the main skeleton, while the smaller ones are found in the dermal membrane. The larger oxea are evenly curved, sometimes the bend is somewhat sharper and localized to the middle of the spicule. The points are evenly pointed and of middle length. The length varies from ca. 041— e>-55 mm , and the I2 o PORIFERA. II. thickness is ca. 0-017 — o - 025 m,n . Besides a great many much finer, very long pointed forms are found, which pass evenly into the thicker ones, and are, no doubt, developmental forms. The smaller oxea are of a quite similar form as the large ones, they are evenly, rather slightly curved, and have also evenly tapering points of middle length. Their length varies from 0-268 — 0-35™™, and the thickness from 0-013 — o-oi8 min . A few intermediate sizes between the two groups may be found. Fine develop- mental forms are also found of the small oxea. 1 ) b. Microsclera; these are of only one form, isochelse arena tse; they are of a quite characteristic form, the shaft is highly bent, but the curve ma)- otherwise be somewhat varying; the tooth forms such an angle with the shaft, that a straight line drawn from one end of the shaft to the other will pass through or along the teeth. The tooth is narrowly ellip- tical, and there is a longish tuberculum broadest downward; the alse are of the same length as the tooth or reach a little farther down, and when the chela is viewed from the side, they end in a round lobe. Sometimes the chela is so highly bent, that the teeth and alse of the two ends meet, and the bend may be so strong, that the teeth and alse overlap each other. This fact leads then to some irregularity, the teeth are bent each to its own side, and they get a more or less wry form; on the other hand I have seen no coalescing, neither between alse nor teeth; a coalescing may often appear to have taken place, but by a sufficiently exact examination it is seen that the parts only pass over each other, but are not coalesced. Together with the strong bend an alteration of the dimensions of the single parts of the chela takes place; both alse and tooth become longer, and from the tuberculum a continuation reaches farther down the tooth. This irregularity of the chelse may in some individuals be of frequent occurrence, so that by far most of the chelae are irregular, while in other individuals it is far more scarce. The length, which is a little dependent on the curve, varies between 0-030 and o-04 mm , and the thickness of the shaft is 0-0033— o-O04 mm . Developmental forms of the chelae are rather frequently found, the youngest forms are fine and have rather short recurved ends; at this stage they may to some degree remind of sigmata; by and by tooth and alae are developed. The chelae are found throughout the tissue, but are specially numerous and very close-lying in the dermal membrane. Embryos. In one of the specimens embryos were found abundantly. They are scattered in the tissue, and each of them is surrounded by a thin membrane. They are about globular, and have an average diameter of about o - 47 mm . The examined ones showed no spicules. As I have had one of Armauer Hansen's type specimens, I have been able to identify the species with certainty; otherwise the determination would have been impossible. The D. clavellata established by Arnesen I.e. I have, likewise by examination of a type specimen, been able with cer- tainty to identify as flabdliformis. Arnesen evidently has only had young specimens; to be sure she states the size to be 25 cm , but the specimen sent to me is only 25""", and the figure of the stalk on Taf. IV, Fig. 4 shows that it is at most a few millimetres thick, so that there can scarcely be any doubt that 25 cm is a misprint for 25""". Locality: The Ingolf, station 7, southeast of Iceland, 63"" 13' Lat. N., 15 41' Long. W., depth 600 fathoms, two large specimens; station 85, southwest of Iceland, 63° 21' Lat. N., 25° 21' Long. W., depth ■) In the mentioned smallest specimen the spicules were a little smaller, the skeletal spicules measuring at most 0-4 i mm , and the length of the dermal spicules keeping near the lower limit. The microsclera, on the other hand, were of full size. PORIFERA. II. 121 170 fathoms, the smallest specimen; it was attached to a stone together with a great many sponges of the genera Myxilla, Hymedesmia, Grayella, Hymeraphia, Plocamia, Bubaris , and Latrunculia. It has further been taken northeast of the Faroe Islands, 62 c 29' Lat. N., 5 17' Long. W., depth 160 fathoms, a small specimen (Ad. Jensen, the cruise of the ,, Michael Sars: 1902). Gcogr. distr. By the Norwegian North-Atlantic Expedition the species was taken west of Spitzbergen, depth 416 fathoms. Arnesen I.e. mentions it from Bergen, at depths of 50 — 60 fathoms. 2. H. palmata Johnst. PL XIII, Fig.6a-c. tiybj- Spongia bacillaris Liune, Syst Nat. Ed. XII, I, 1299, 13. ? I77 6. — Midler, Zool. Dan. Prodr. 256, 3086. ?I786. Spongia palmata Ellis and Solauder, Nat. Hist, of many cur. and uncom. Zoophytes, 189, PI. 58, fig. 6. 1797. Spongia digitata Esper, Fortsetz. der Pflanzenthiere I, 190, Spong. Tab. L. 1842. Halichoudria palmata Johnston, A History of Br. Spong. and Lithophyt. 92, 1, PI. II, figs. 1 — 5. 1866. Isodictya palmata Bowerbauk, Mon. Brit. Spong. II, 311, 25. 1870. Pachychalina compressa O. Schmidt, Grundzuge einer Spougienf. des atlant. Gebiet. -yj. 1870. Homceodictya digitata Ehlers, Die Esperschen Spongien, Erlangen, 16, 32. 1874. Isodictya palmata Bowerbank, 1. c, III, 133, PL LII, figs. 1 — 7. 1879. Verrill, Preliminary check-List of the Marine Invert, of the atl. Coast fr. Cape Cod to the Gulf of St. Lawrence, 31. 1882. Chalina palmata Carter, Ann. Mag. Nat. Hist. Ser. 5, X, 109, fig. i,a, b. 1896. Homa'odictya palmata Lambe, Trans, of the Roy. Soc. of Canada, Ser. 2, II, Sect. 4, 190, PL II, figs. 1, 1 a — f. Of Chalina-like appearance ; erect, more or less regularly digitately branched, the branches more or less, often highly, compressed, frequently to a larger or smaller extent coalesced to plate-shaped parts. The surface finely and densely shaggy from the projecting ends of the fibres. The dermal membrane a thin film resting on the skeleton below and pierced by the ends of the fibres. Oscula partly scattered, partly placed along the edges of the compressed branches or chiefly on one side of them. The skeleton constructed as in Chalinius. forming a regular reticulation of polysplenia r primary fibres bending towards the surface in a sheaf-like way, and secondary fibres perpendicular on the primary ones , the meshes quadratic or rectangular. The fibres provided with a distinct sheath of spongin. Spicula: Mcgasclcra oxea o-fj — o-22g"""; microsclera of one form, isochelce palmata- with the axis bending out as a projection from the inside of the tooth 0-024 — o'oj""". The common exterior form of this species is well known, and it has often been figured, espe- cially, however, in earlier works. It has attracted the attention at an early period, and its exterior has given rise to the name of Mermaid's glove , by which it is said to be designated by the fisher- men of the Orkneys and the Shetland Islands; however, it certainly shares this name with the digi- tately branched forms of Pachychalina. In its exterior and otherwise also in its skeletal structure it The Ingolf-F.xpedition. VI. 2. 16 I22 PORIFKRA. II. shows great resemblance to Chalinina, especially to such forms of Pachychalina as the mentioned ones. This resemblance is very great and is also found in the form of the megascleres, so that, properly speaking, it is only by the occurrence of the characteristic chela that it can be decided, whether a specimen belongs to a /doi/i/rod/clya-species, and confoundings have certainly now and then taken place. In the form a frequent feature seems to be that a compression of the branches takes place, and that larger or smaller portions of the lower part of the sponge form flat parts only branching above or in the edge. This form seems to be rather constant in the species, and to stand somewhat opposed to the common form of the Pac/iyc/iali/ia-species most resembling it. This difference is especially found as a rule, but not always, between the present species and the Pac/iye/ial/na-species (P. excelsa Schmidt) most common in the North-Sea. Of the species we have a rather considerable material showing the variations of the form. A few specimens have a regular digitate form with only a slight compression of the branches, especially in their lower part, while their upper end is cylindric or almost eylindric. Several other specimens are less regular, with more compressed branches and more expanded parts below, or the expanded parts become larger, and prevail almost over the in this case shorter branches; finally we have one specimen, the branches of which are exceedingly flattened and are lying in one plane, so that this specimen gets a very great breadth. The smallest and youngest specimens are quite unbranched; and these small specimens are most frequently formed as a single compressed branch or about oar-shaped, but irregularities may also occur at an early stage, so that the smaller specimens form broad, flat, somewhat lobate bodies. The smallest one of all the specimens, which is attached to a stalk of a Hydroid, is almost globular. Sometimes the lower part is more or less marked off as a stalk, but the branching may also begin directly at the base. Most of the speci- mens are torn off from the underlayer, of the others one is attached to the shell of a Modiola modiolus, a few others partly to worm-tubes, partly to stalks of Laminaria. The number of branches is very varying; the most richly branched specimen is above divided into about a dozen branches, but gener- ally the number is smaller. The largest specimens are 34 cm high, and the regular, digitate branches have an average breadth of about 25"""; then follows a series of specimens of decreasing sizes. The largest of the smaller, unbranched specimens has a height of i3 cm , and the smallest one is 7-5 cm high. The mentioned, still smaller, globular specimen has an extent of only 8 mm . The consistency is very elastic, quite as in the C/iali/icr. The colour (in spirit) is generally light yellowish gray. The surface is finely and densely, but quite short shaggy from the projecting ends of the fibres. The dermal membrane is a thin and transparent film; it has no spicules, but rests on the skeleton beneath and is pierced by the ends of the fibres. The pores are found in the dermal membrane, often so closely placed that the membrane is reduced to a network; they are round or a little irregular and were measured to a diameter of 0-03 — o-i2 mm . Oscula are circular or, more rarely, somewhat oval openings; they are surrounded by a projecting, more or less pronounced, conical edge. They are directed some- what upward, and consequently the projecting edge is higher on the lower side of the osculum. The principal canal runs obliquely downward, but larger canals may frequently be seen to lead into the principal one from different sides. Oscula vary in size from 6 mm quite down to i mm . They occur in rather large numbers and are found from the very base of the sponge to the top of the branches. Sometimes they may be said to be scattered, but most frequently their occurrence is limited to definite PORIFERA. II. 123 places. Thus thev are often found on the edges of the compressed branches, but most frequently some of them are then found scattered on the surfaces. In the highly flattened specimen mentioned before the}' are found, partly on the edges, partly rather abundantly scattered over one surface, while on the other surface only quite few are found; and they may, in the regularly digitate specimens, be found almost exclusively on one surface. The skeleton is constructed quite as in a PacJiyclialina. It consists of polyspicular fibres passing upward from the base and the middle, branching and bending to all sides in a sheaf-like way, and going to the surface. These primary fibres are connected by transverse fibres that are placed perpen- dicularly on them but form no coherent fibres. Thus a regular net of meshes is formed, which is onlv less regular in the middle part of the bod)-. The meshes formed by the fibres are quadratic or rectangular; towards the surface the transverse fibres are placed considerably more closely than farther in. The distance between the primary fibres may be somewhat varying, and was measured to ca. ot8 — 0'4 m,n . The thickness of the primary fibres is generally about o-oo, mm . A distinct and most frequently rather thick sheath of spongin is always found round the needles both in the primary fibres and in the transverse ones. In the points of the fibres the mass of spongin is slight, and forms no sheath; this fact is especially distinct in the points of the branches, where the growth more particularly takes place. Quite as in the Chalinina, layers are also here found in the branches, which layers are more or less parallel to the surface, and quite recall the structure of the outer skeletal layer, and these layers have presumably during the growth of the sponge marked the close of a period of growth. The layer arises by the fact that transverse fibres are here placed opposite to each other through the whole extent of the layer, while these fibres on both sides of the layer, as well outside it as inside it, are placed more scattered, often with rather long intervals. Then small short, primary fibres are found reaching from the layer of transverse fibres a little outward between the primary ones, but continuing no farther. Thus it looks, as if, by the beginning of a new period of growth, only some of the primary fibres that project through the surface continue the growth. Both the mentioned structural features cause the mentioned layers to appear as layers of more dense consistency, when a dried specimen of the sponge is seen towards the light. Already Bowerbank mentions this feature, I.e. II, 312. Scat- tered spicules are found rather copiously outside the fibres. Spicula: a. Mcgaselera are oxea; they are straight or slightly curved, and evenly, middle long or rather long pointed. The spicules are very varying, both in length and thickness; the length varies from about 0-15— o-229 mm , and the thickness from about 0-008— o-oi7 mm . The largest spicules are of most frequent occurrence. It is, however, difficult to give the lower limit of the thickness, as some developmental forms are found passing evenly into the fully developed needles. With regard to the size of the needles, especially the thickness, some slight difference may be found between different individuals. Styli are not rarely found between the needles; they are always shorter than oxea, and they must surely be regarded as monstrous forms; in some individuals they are found more frequently than in others, b. Microsclera; these are only of one form, isochelse palmatae of the peculiar type before mentioned. When the chela is seen in profile, it looks as if the end of the tooth was split into two branches, one of which continues towards the axis. The inner branch is the end of the axis of the chela, which bends out from the tooth and in towards the axis. When the chela is seen I2 _| PORIFERA. II. from the front, therefore, a little below the oblong tuberculum proper another oblong, tubercle-shaped body is seen, which is the translucent, recurved end of the axis. The aire form together an oval plate, and their edges are a little refolded. The plates formed by the alse of both ends continue along the axis as a most frequently quite narrow ridge, and this part arches somewhat out from the axis behind, so that the back side of the chela is somewhat curved, although the axis is straight. When the chela is seen in profile under strong light, the axis may distinctly be followed, as it is more transparent than the tooth and aire, which are seen from the edge. Then, in the first place, the inward-turned terminal part of the axis is distinctly seen, next a part appearing as a hump on the outside of the tooth, and finally the middle, straight part of the axis (PI. XIII Fig. 6 b). These features are not always easily seen in the fully developed chela, especially as the different parts of the axis are differently developed; thus the falx is rather broad, and the inward-turned terminal part grows often very thick. Otherwise, with regard to length and form of this part, the chela may be rather varying; sometimes, also, the axis, and consequently the whole chela, is somewhat curved. The thin ridge in the middle of the cheia may vary to some degree in breadth. The length of the chela varies from 0-024— 0-03"™, and its greatest breadth is ca. 0-007 — ooo8 mm . Developmental forms of the chela in all stages occur rather frequently; the finest ones consist only of the axis, which, according to what has been stated above, is straight and recurved at either end in such a way as to form an eye turning to one side; then the aire and the plate of the tooth are formed by and by. The chelae occur both scattered in the tissue of the sponge and in the dermal membrane, but upon the whole in no large numbers. Bowerbank's description and figures of this chela are quite incomplete; thus his figure of the profile does not show the peculiar continuation of the axis, but the chela is, however, tolerably recognisable, especially from the figure showing it from the front. His description, on the other hand, is quite erroneous. Carter 1. c. gives a good figure of the chela seen as well from the side as from the front, but in his description there are several misconceptions. Ridley and Dendy (Challeug. Report, 108) say, in their description of the chela in the generic diagnosis, from the median line of the posterior surface of each anterior palm there projects backwards, i. e. towards the shaft, a delicate, flat fimbria-; according to this expression these authors do not seem to have seen that the question is of the axis of the chela; neither is it correct, when they term the inwardly-directed process delicate, flat , although, to be sure, it is frequently somewhat compressed. Also their figures of the chela, especially in the species grandis, show that the process is here quite cylindrical. Locality: From Iceland and the Faroe Islands we have a rather considerable material. From Iceland: Skagen (Gronlund), off Rodsands Bay (Hj. Jensen), Onundarfjord, depth 10 fathoms (the author); Iceland, no more particular locality stated (Jap. Steenstrup, Halberg). From the Faroe Islands: 6 miles N.W. of Kalso, depth 60 fathoms, Vestmansund, depth ca. 70 fathoms, 9 miles east of Nolso, depth 30 fathoms (Th. Mortensen) ; the Faroe Islands, no more particular locality stated (Nees, Rostrup, Miiller). Seventeen larger and smaller specimens in all. Geogr. distr. North-England, Scotland, the Shetland Islands and the Orkneys (Johnston, Bower- bank); Norway (Esper, Ehlersl. c); New Scotland, Sable Island, and the Bay of Fundy (Lambe); between Cape Cod and the Gulf of St. Lawrence (Verrill). Thus the species is distributed between ca. 66° and PORIFERA. II. 125 44 Lat. N., but on the eastern side of the ocean it is known no farther south than to the coasts of England. It is not found in deep water, the greatest depth known being ca. 70 fathoms. Remarks to the synonymy. This species is generally enumerated as palmata Jolmst., and Carter (1. c.i having examined Johnston's type specimen and found the characteristic chela, the identification may also be regarded as sure. The species may, however, with certainty be traced farther back, Ehlers (1. c.) having shown by examination of Esper's type specimen of Spongia digitata that this species is identical with Johnston's palmata, what was also indicated by Esper's figure. Therefore there might be some reason for taking up Esper's name of digitata, which dates from 1797. I have not done so, however, as there is great probability that Spongia palmata Ellis and Solander, 1786, is the same species. The description, to be sure, gives no hold, but the figure of the exterior, showing the characteristic compression, seems to show, even if not quite certainly, that the question is of the present species. Linne's name of Spongia ba cilia r is, on the other hand, cannot be taken up, as it is impossible to decide, whether he has had before him the present species or some Pachycha lina-iorm. - By the examination of Schmidt's type specimen of Pachychalina compressa I have been able to decide that this species is identical with H. palmata, as already mentioned in part I of the Porifera of the Ingolf-Expedition, p. 6. Group 2. Myxilleae. Megasclera generally divided into two forms, those forming the dermal skeleton, and those forming the main-skeleton. Typically the skeletal spicules are monactinal and the dermal spicules diactinal, but exceptions from this rule occur. It seems to be a rather important character of the group Myxillece that the skeletal spicules are of one form and almost always monactinal, the dermal spicules of a different form and most fre- quently diactinal. The reach of this character, however, cannot yet be decided. In the group Mycalece, to be sure, instances may be found where the spicules that in some way or other belong to the dermal membrane are smaller or of a form somewhat different from those of the principal skeleton, for instance .17. placoidrs, some Espcriopsis-species, Artemisina, Homceodictya flab elisor mis, but they are generally of the same type. In the following subfamily, Ectyoniiur, which is closely allied to Myxillece, on the other hand, some genera are still found showing the difference, characteristic of Myxillecr, between the dermal spicules and the skeletal ones, and still here the system is scarcely a natural one. The dermal spicules in Myxillece are generally briefly stated to be diactinal; this statement, however, is not quite correct. As will be mentioned in the following under the single species the equi-ended dermal spicules, whether they be strongyla, tornota, or tylota, are only secondarily diactinal, but really monactinal, as they are begun as monactinal and grow as such to about their full length, and then the final form only occurs by degrees, contemporaneously with the growth in thickness. In the not quite developed spicules this development may still be traced, the ends being not quite equal, and it is no rare fact that the ends upon the whole never become quite equal, but it may still be decided in the fully developed spicules, which end has been the original point. The general fact is, accordingly, that the finer, i. e. the younger, the dermal spicules are, the greater is the difference I2 6 PORIFERA. H. between their ends, and the more they approach the monactinal form. This rule seems to be a gener- al one; it is to be noted, however, that in the new genus Dendoricella established below, the dermal spicules are really diactinal. I have not yet been able to decide, whether these features may get any systematic importance. It is, accordingly, to be remembered that when in the following the dermal spicules in diag- nosis and description are called diactinal, this term is a purely descriptive one and means only that in their final form the spicules are more or less equi-ended. Dendoricella n. g. (Damiria Topsent). The form massive, lobate or erect, club-shaped. The skeleton polyspicular, irregular or dendritic; the dermal skeleton consists of more or less erect bundles of dermal spicules. Spongin present or wanting, Spicula: Megasclera : the skeletal spicules diactinal. oxea (or strongyla). the dermal spicules oxea. tornota. or tylota ; microsclera chc.hr arcuatcr solely, or chela" arena fir and sigmata. Topsent (Archiv de Zool. exp. et gen. Ser. 2, X, XXI) mentions the genus Damiria Keller, and characterizes it as being distinguished from Dendoryx (in Topsent's sense) by its diactinal skeletal spicules. Later has for instance Lindgren followed Topsent in this view. Weltner, however, (Zool. Anzeig. XXI, 1898, 429) has shown that Damiria Keller has by its author been correctly referred to the Renierids, and has nothing to do with the Myxillae, and after having examined a frag- ment of the type specimen kindly sent me by Dr. Weltner I can only corroborate this view. For the generic conception which Topsent in the quoted place calls Damiria we must thus have a new name. Ridley has referred a species belonging here to the genus Crella Gray (Cribrella O. S.), but Thiele (Kieselschwamme v. Ternate II, Abhandl. d. Senckenberg. nat. Gesell. XXV, 953) has correctly rendered an accouut of the fact that the type of this genus, C. clegans O. S., is a quite different sponge. Thiele means, in the place quoted, that the species belonging here may be kept in the genus Myxilla, whereas my opinion is that it is necessary to place them in a separate genus with the diag- nosis given above, and I call this genus Dendoricella. Its most important character is that the skeletal spicules are plainly and really diactinal. The eldest species of the genus is D. Schmidtii Ridley (Zool. Coll. of < Alert-, 432, PI. XLI, fig. aa). Dendy has later (Proc. of the Royal Soc. of Vict. VIII, 28) established a species, D.australicnsis, which is. however, according to Topsent (Rev. Suis. de Zool. IV, 455) identical with Schmidtii. Topsent, in 1892, (Archiv de zool. exp. et gen. 2, X, XXII) has established two species (under Damiria), caver- nosa and Prouhoi ; of these species the latter has certainlv not really diactinal spicules, but is, no doubt, a Jl/yxilla (see below under M. brunnea); the former species, cavernosa. I think to be a Dendo- ricella. Finally Topsent (Resultats de Campagn.scient.du Prince de Monaco, Fasc. XXV, 240, PI. Ill, fig. 3, PI XIV, fig. 12) has established a species, abyss/', which, remarkably enough, he refers to Dcsma- cidon, although it is a sure Dendoricella. Of Carter's Halichondria infra/ u ens (Ann. Mag. Nat. Hist. PORIFERA. II. 127 Ser. 5, VII, 309, PI. XVIII, fig. 9 a— d) nothing can be said at present, and it is very doubtful whether it belongs here. Thus the species of the genus Dendoricella will be as follows: 1884. D. (Crella) Schmidtii Ridley, with oxea, tylota, chelae, and sigmata. 1892. - (Damiria) cavernosa Tops, with strongyla, tylota, chelae. (Of what kind these chelae are can- not be decided from the description, in which it is said a bouts pectines».) 1903. - (Desmacidon) abyss/ Tops, with oxea, tornota, chelae. - rhopaluin 11. sp. with oxea, tornota, chelae. - obesichela n. sp. with oxea, oxea, chelae, and sigmata. The Myxilla grata established by Thiele 1. c. has evidently, to judge from the figure, not reallv diactinal skeletal spicules, but styli with rounded end, and is either a Myxilla or perhaps a Lis- sodendoryx in the sense in which I take this genus; the fact is that it cannot be seen from the figure, whether the species has chelae or aucorae. When Ridley referred the species Schmidtii to Cribrella = Crella, the more particular reason was, I suppose, the arrangement of the pores in sieves. Characteristic as this feature may be, it is a character that is found in many sponges, and cannot be used for an establishing of genera; it is only a further development of the feature found in a great many sponges in which the pores are especially placed over the subdermal cavities. Of Schmidt's four Cribrclla-species hamigera is now the type of the genus Hamigera ; elegans, which has smooth oxea in the principal skeleton, spined oxea in the dermal membrane, and further spined styli, I suppose to be identical with Topsent's genus Pytheas, in which case this genus may be called Crella; liospitalis and papulosa, as mentioned by Top sent, belong to the genus Yvesia Tops., which genus, what Thiele has drawn my attention to, must be called Grayella Cart, with the typical species cyatophora Cart. --Of the Dendoricella-species rhopalum shows the mentioned character of sharply limited pore-grooves to a strongly marked degree; the structure seems to be rather similar in abyssi and Schmidtii, but it is not mentioned with regard to cavernosa. The two species described here, and abyssi are natives of deep waters, from 799— 2596 fathoms; Schmidtii and cavernosa, on the other hand, are from shallow water. The genus Dendoricella must among MyxillccB be the one most closely allied to the preceding group, as it approaches Homceodictya ; among the Homajodictya-apecies a few are found, in which the spicules of the dermal membrane are smaller than those of the skeleton, but they are of one form; in Dendoricella, on the other hand, two forms are found. 1. D. rhopalum n. sp. PI. IV, Figs. 4^5. PI. XIV, Fig. 1 a-e. Club-shaped, often somewhat compressed, sometimes a little lobate above. The surface with close- st, more or less deep grooves, separated by ridges arranged in a net-like zvay, slightly shaggy. The dermal membrane a thin film, supported by bundles of dermal spicules. Oscula more or less spout-shaped, one or several, on the tipper part of the sponge. The skeleton dendritic, polyspicular. Spicula: Mega- I2 S PORIFERA. II. sclera: the skeletal spunks oxca o-68 — o-g8""", the dermal spicules tornota approaching oxea 0-45 — o-<5 ■,-""",• microsclera of one form, isochela arcuatm 0-034 — 0-0429""". This species is most frequently markedly club-shaped. The specimens in hand that are not torn off from the under-layer are attached to larger or smaller stones. At the place of attachment they have a quite slight basal expansion, from which they rise increasing more or less evenly in thickness; thus no real stalk is formed, but the thinnest part is always found just above the basal expansion. Sometimes the upper part is more or less regularly cylindric like the lower part, but most frequently it is more or less compressed, sometimes in such a way that one side is convex, the other flat or concave. Most frequently the club-shape is rather slender, but it may be shorter and thicker. In a few cases the form is a little modified, the upper part being a little lobate; thus we have one specimen, which is, almost through its whole length, divided into three wing-like lobes. In one case the club is divided above into four quite short processes provided with oscula. The largest specimen is ca. cp™" 1 high; it is compressed, and has a breadth of ca. 50""", and a thickness of ca. i2 m,n , just above the basal expansion the thickness is ca. io mra . The smallest specimen, which is more cylin- drical, is 24 mm high and 7 m,n thick. The consistency is rather firm and, on account of the skeleton, rather solid, and it is also somewhat elastic. The degree of contraction of the sponge causes, however, a considerable difference with regard to the consistency, the most contracted ones being considerably harder than those not contracted. The colour (in spirit) is in most specimens light gray (stations 20 and 36); in some specimens it is a little darker with a brownish tint, so that it becomes light grayish brown (station 18). The surface is very characteristic, but it has a rather different appearance, accord- ing as the sponge is contracted or not Its appearance is most characteristic in the highly contracted individuals; in these it is closely set with rather deep grooves separated by narrow, ridge-shaped walls; these walls form a peculiar net all over the sponge, imparting to it an appearance highly recalling that of Nardoa reticulum. The less contracted the sponge is, the flatter these grooves become, and they may also quite disappear. The grooves are nothing else than those occurring in so many sponges, for instance in AL incrustans, which are formed by the dermal membrane being sunk between the parts of tissue separating the subdermal cavities, but they are here more regular and always sharply bounded from each other. The less contracted the sponge is, the larger and more shallow are the grooves, while they become smaller and deeper in the contracted sponge, and in this latter they are often oval. Their size is between about 0-4 and 3 mm . The grooves, especially in the contracted sponge, have a rather sharp edge. The surface is so far shaggy, as the dermal spicules project a little every- where between the grooves. The dermal membrane is an exceedingly thin, transparent film, resting on the bundles of dermal spicules projecting from the ridge-shaped walls, and stretched over the inter- jacent subdermal cavities. The pores are situated in the parts of the membrane stretched over the subdermal cavities, and these parts are accordingly pore areas; in these areas they are found in large numbers and very close-set, so that the membrane becomes a sieve. Their size was measured to 0-03 — o-4o mm . Oscula are found to a number of from one to ca. ten, evidently in proportion to the size of the sponge. They are found on the top of the sponge or a little down on the side; the largest speci- men shows ten oscula, but it is somewhat damaged, and has perhaps had more than ten; they are all PORIFERA. II. 129 placed rather close together along the upper edge. In the above mentioned specimen which divides above into four processes, three of these processes have each an oseulum, while the fourth one has two oscula. Oscula are spout-shaped, a pointed, conical spout rising to a greater or smaller height round the opening, which spout is formed by the dermal membrane; it is most frequently somewhat twisted. In the membrane forming the spout dermal spicules are found, arranged parallelly to the longitudinal axis of the spout, more or less gathered into fibres; these fibres arise from the fibres supporting the dermal membrane, which continue into the membrane forming the spout. From the oscular opening a rather wide canal continues far down in the sponge, running chiefly in the longi- tudinal direction, but frequently irregularly curved. The skeleton. The dermal skeleton. The outermost branchings of the main skeleton towards the surface are continued by short fibres of dermal spicules. The outermost spicula-bundles of these fibres are spread in a penicillate or fan-shaped way, and they extend everywhere into the ridges between the pore grooves, and project a little over the surface; horizontal spicules are not found, and the fibres are arranged in such a way as only to be found in the ridges. In different places of the sponge these fibres may be differently directed, perpendicular to the surface or more or less recumbent; thus they are frequently directed towards the upper end of the sponge, and accordingly recumbent, when a piece of the membrane is seen from above. The fibres formed by the dermal spicules are most frequently about i mm long. The arrangement of the dermal skeleton reminds much of the structure in Artemisina arcigera. The main skeleton is of dendritic type. From the base a few thick fibres rise, branching grad- uallv up through the sponge, frequently coalescing and connected by more or less strong anastomoses in different wavs, so that a chiefly dendritic, tolerably regular and rather densely branched skeleton is formed. The outermost ramifications of the skeleton bend towards the surface at right or more or less acute angles. Then these outermost ramifications of the skeleton, as mentioned above, continue to the surface as fibres formed by dermal spicules. All the fibres are polyspicular, towards the base they mav be very thick, up to o-5 mm , and they are here interwoven with a network of more or less strong anastomoses. The outermost ramifications, just before the beginning of the dermal spicules, have a thickness of ca. o-09 mm . Spougin is found in the fibres, which are, therefore, very solid, but the spongin is white and clear, and so it is only to be observed with difficulty. In the lower part of the sponge it coats the fibres entirely, but only with a very thin layer; farther up the spougin is more scarce, and it is not seen in the dermal fibres. Spicula: a. Megasclcra. 1. The skeletal spicules are long oxea; they are slightly, rarely a little more, curved; the curve is most frequently even, sometimes it is a sharper bend and localized in the middle. The spicules are of about equal thickness throughout the length, and the point is middle- long, frequently bounded by straight lines. The length is o-68— cr98 ram , most frequently nearer to the latter limit than to the former; the thickness is 0-014— o-022 mm . A few developmental forms are seen, all of which are long pointed. 2. The dermal spicules may be best described as tornota, but they approach the form of oxea; they taper a little from the middle outward, the point may be somewhat varying, but most frequently it is short. They are generally straight, sometimes a little curved. Their length is 0-45— o-65 mra , their thickness ca. 0-007— o-on mm . Of this spicule very few developmental forms were seen, and no quite young ones. But to judge, both from the quite equally formed ends of the The Ingolf-Expedition. VI. 2. 17 130 PORIFERA. II. fully developed forms and from the few developmental forms, this spicule seems to be really diactinal. b. Microsclera; these are only of one form, isochelae areuatae. The chelae are elegantly formed, the shaft is evenly and rather highly curved, the terminal parts are comparatively small in proportion to the length of the chela. The alae are drawn out to a pointed corner, and are somewhat tooth-like; the tooth is narrowly lanceolate, pointed downwards, and there is a small, oblong tuberculum. The shaft is not quite cylindrical, but a little compressed ; this compression may be more or less pronounced, and the dorsal side of the shaft may thin to a more or less broad brim. In this respect there may be great difference in different individuals. In some individuals the shaft is only little compressed, and only very few chelae show a slight brim; in others chelae with brim and without brim are about equally frequent, and in one specimen almost all the chelse have a brim, and only few are found without brim. The more frequent the chelae with brim are, the broader is the brim. In the specimen in which almost all the chelae are provided with a brim, this brim has frequently one or two incisions, so that it is divided into two or three lobes. In by far most individuals the brim is narrow, and in most of the chelae it is wanting, so that it seems as if its higher development is to be regarded as a monstrosity. The length of the chelae is 0-034— 0-0429"™, and the thickness of the shaft is between 0-0014 and o-oo29 nim , according as it is seen from the front or from the side; in chelae with large brim the breadth of the shaft may reach o-oo50 mm . A few developmental forms were seen; the fine ones had a recurving at either end, but did not yet show any traces of alae. The chelae are found through- out the sponge, and they are abundantly present everywhere in the dermal membrane, besides in other places they are close-lying in the pore sieves in the strings of tissue between the pores. Locality: Station n, 64 34' Lat. N., 31 12' Long. W., depth 1300 fathoms, one specimen; station 18, 6i° 44' Lat. N., 30 29' Long. W., depth 1135 fathoms, three specimens; station 20, 58 20' Lat. N., 40 48' Long. W., depth 1695 fathoms, six specimens; station 36, 6i° 50' Lat. N., 56 21 Long. W., depth 1435 fathoms, ca. ten specimens. The stations are situated in the Denmark Strait, south of Greenland, and in the southern part of the Davis Strait. The species is evidently a deep-water species, 1135 fathoms being the smallest depth, at which it has been taken. All the specimens are more or less, some to a very high degree, filled with the light-gray mud of which the bottom at the mentioned localities consisted; in it is found a great many Foraminifera and Coccoliths. This filling may, however, at all events partly, have taken place in the trawl. Remarks : This species seems to be rather closely allied to the above mentioned D. abyssi Tops, whose chelae, to judge from the figure, have a somewhat similar form, and whose dermal spicules are tornota. Also this species is a native of considerable depths, between ca. 2000 and 2500 fathoms. Top- sent mentions that it, like rhopalum, contained much bottom material. 2. D. obesichela n. sp. PL XIV, Fig. 2 a-d. Form? The dermal membrane thin, supported by bundles of dermal spicules. Spicula: Mega- sclera: the skeletal spicules oxea 0-54 — 075""", the dermal spicules oxea o-j2 — o--/-/""*.- microsclera of two forms, chela' arcuata: 0-026 — o'ojjy""". sigmata o m 02i — o'o6j""". PORIFERA. II. 131 Of this species we have only a small, poor fragment, so that the description must chiefly be restricted to the spicules. As to the form of the sponge nothing can be said; the fragment is longish and has a greatest extent of i4 mm . The consistency is of a middle firmness. The colour (in spirit) is yellowish. The dermal membrane is mostly destroyed; it seems to have been a thin film, supported in the common way by dermal spicules. Pores and oscula were not seen. The skeleton. The dermal skeleton consists of dermal spicules, and, in spite of the destroyed dermal membrane, it may be seen to have been arranged in the common way as more or less erect, penicillate bundles. As to the main skeleton, on the other hand, I can say nothing definite, as the fragment in hand may perhaps have been highly squeezed and pressed; in its present state the skeleton appears partly as irregularly arranged spicules and partly as spicula-bundles. No spongin was to be seen in the skeleton. Spie 11 la: a. Megasclera. 1. The skeletal spicules are oxea; they are slightly curved, evenly tapering, and the point is rather long. Their length is 0-54— 075™™, the thickness is ca. cron — o-oi7 mn) . 2. The dermal spicules are also oxea, but by the form of their ends they approach somewhat to tornota; thev are straight or quite slightly curved, and they taper a little towards the ends, the point is even, but short. Their length is 032 — o - 44 mm , and the thickness in the middle is o-oo6— o-oio mm . b. Microsclera; these are of two forms, chela; arcuatse and sigmata. 1. The chelae arcuatse are of a rather broad and compact form, the shaft is rather highly curved, the tooth is elliptical, more or less rounded, sometimes a little cut off at the end; there is a tuberculum, pointed downward; the alae are of the same length as the tooth, and are more rounded. In contradistinction to the chela of the preceding species the shaft is here highly flattened. Their length varies from 0-026 — o-0429 n>m and the thickness of the shaft from 0-0025— O'0o85 mm , according as it is seen from the side or from the front. Very few developmental forms were seen; they are already highly flattened at an early stage. 2. Sig- mata; these are of the common form and more or less contort; their length may upon the whole vary from 0-02 1— o-o64 mra , but it is rarely less than o-043 mm , so that the small forms are rarely seen. The thickness is upon the whole 0-0014— o-oo28 mm . Both forms of microsclera occur in very large numbers, and through the whole sponge; the chelse are seen in enormous numbers closely packed in the dermal membrane. Locality: Station 78, 6o° 37' Lat. N., 2 f 52' Long. W., on the eastern slope of the Reykjanaes- ridge, depth 799 fathoms. Myxilla O. Schmidt. (Dendoryx Gray 1867). The form varying, from inc rusting to lumpily massive, cushion-shaped, or forming more or less round masses, sometimes somewhat lobate; then more or less irregularly leaf-shaped, or finally club-shaped, stalked. The skeleton a polyspicular reticulation, which may be more or less irregular, sometimes rather diffuse. In the erect forms longer, primary fibres are found. It is no rare form that the reticulation consists of triangular meshes, which may be more or less regular. The dermal skeleton consists chiefly of erect bundles of dermal spicules, sometimes also horizontal spicules are found. Spongin is found, but almost always 17* j, 2 PORIFERA. II. to a very slight amount. Spicula: Megasclera: fin: skeletal spicules styli\ most frequently spiiied, sometimes smooth, the dermal spicules diactinal, strongyla, tornota, tylota, or similar forms, the ends may be vari- ously formed, and spined or smooth ; microsclera, ancorce. spatuliferce, sometimes of two forms, most fre- quently three-toothed, sometimes with more teeth; further sigmata may be added. In 1862 O. Schmidt established the genus Myxilla with the species rosacea Lieberkiihn. In 1867 Gray established the genus Dendoryx, and as the first species under it he mentioned incrustans Johnst. In 1887 Vosmaer, in Porifera, Bronn's Klassen und Ordnungen , has the families Dcsma- cidonida- and Ectyouidcc, and he places Myxilla to the former family, and has Dendoryx with a query as a synonym to Hastatus, which, as is well known, is identical with Myxilla. In the same year Ridley and Dendy in Challeng. Report, under the family Dcsmacidonidce, have the subfamilies Esperelliiur and Ectyoniucr, and here they place the genus Myxilla to the latter subfamily. They render a detailed account of the fact that the genus comprises as well species with accessory spicules as species with- out such spicules, but they have not wished to divide the genus. In 1S8S Top sent (Arch. de. Zool. exp. et gen. Ser. 2, V, bis, 114) revives Gray's Dendoryx, and in 1892 he places the species without accessory spicules in Dendoryx, while he places the species with such spicules in Myxilla. Then Dendoryx is placed under Esperellincr and Myxilla under Ectyonince. Thiele, however, in 1903 (Kieselschwamme von Ternate, II, Abhandl. der Senckenberg. nat. Gesell. XXV, 953) renders an account of the fact that the genus Dendoryx, as Topsent understands it, ought to be called Myxilla, as the typical species of Myxilla, rosacea Lieberk., according to Topsent (Mem. de la Soc. zool. de Fr. VII, 15, footnote 4) is identical with incrustans Johnst. Even if this view, as will be seen below, is not correct, the name of Myxilla will have to be used, as rosacea is, at all events, a species without accessory spicules. 1. M. incrustans Johnst. PI. IV, Figs. 6, 7. PI. XIV, Fig. 3 a-h. 1842. Halichondria incrustans Johnston, A History of Brit. Spong. and Lithophytes, 122, PI. XII, fig. 3, PL XIII, fig. 5. 1842. Halichondria saburrata Johnston, ibid. 120, PI. XI, fig. 3. 1866. Halichondria incrustans Bowerbank, Mon. Brit. Spong. II, 249, 14. 1870. Isodictya fmbriata O.Schmidt (non Bow.), Grundziige einer Spongienf. des atlant. Gebiet. 56. 1874. Halichondria incrustans Bowerbank, 1. c. Ill, 108, PI. XLIV, figs. 7 — 12. 1885. Myxilla barentsi Vosmaer, Bijdr. tot de Dierk. i2te Aflev., 3die Gedelt, 27, PI. IV, figs. 15—16, PI. V, figs. 56-59. 1885? Hastatus Robertson/ Fristedt, Kgl. Sv. Vet. Akad. Handl. 21, Nr. 6, 34, Tab. Ill, Fig. 4 a— b. 1886. Desmacidou incrustans Marenzeller, Die osterreich. Polarstat. Jan Mayeu, III, 10, Tab. I, Fig. 2. 1887? Hastatus Robertsoni Fristedt, Vega-Exp. Vetensk. Iakkt. IV, 442. 1S88. Dendoryx incrustans van typica Topsent, Arch, de zool. exp. et gen. Ser. 2, V, bis suppl. 118, PI. VI, fig. 16 a. 1890. Dendoryx incrustans Topsent, Mem. de la Soc. zool. de Fr., 201. PORIFERA. II. j,. 1S93. Myxilla incrustans Levinsen, Det vidensk. Udbytte af Togter, 419, 17, Tab. I, Fig- 3 1 — 34- 1896. Dendoryx incrustans Topsent, Resultats scient. de la Campagne du Caudan», 274, 15. 1896. Myxilla incrustans Lambe, Transact, of the Royal Soc. of Canada, Ser. 2, II, Sect. IV, 191, PI. I, figs. 10, 10 a — d. Incrusting, forming irregular, massive masses, or being more roundish lumpy. The surface with sinuous grooves, more rarely even, not shaggy. The dermal membrane a thin film supported by peuieil/afe bundles of dermal spicules. Oscula scattered, sometimes on the top of low cones. The skeleton chiefly a polyspicular reticulation of triangular meshes, sometimes more irregular. Spicula: Megasclera: the skeletal spicules acauthoslyli with, scattered spines o-ig — o-jj""", the dermal spicules tornota with slightly spined, rarely smooth ends cny — 0-26"""; microsclcra of three forms, aucorcc spatulifene of two sices, large ones o-ojS—o-O//""", small ones o-oij — 0-028, sigmata 0-024 — 0-075""". This species may vary rather much in appearance, and in this respect it recalls Halichondria panicea. As in this species, however, the form is highh dependent on the substratum on which the sponge is growing. The most frequent forms are more or less extended, incrusting masses that may be thinner or thicker; then it may rise to cushion-shaped bodies or to irregular, roundish lumps. When growing on Algae, roots of Algae or similar bodies, it may have a quite irregular form, but then it is most frequently only incrusting. Oscula may sometimes be found on more or less distinct, conical projections on the cushion-shaped or lump-shaped sponge. The species seems sometimes to be growing directly on the sea-bottom ; a few of the specimens in hand are not attached, but their basal surfaces are filled with sand and gravel. According to Johnston and Bower bank, it is also frequently found on rocky bottom, growing on the rock. It is very often growing on P^Arw-species, and then it is most frequently rather regularly cushion-shaped or flatly semiglobular. In the Iugolf-material we have it on Pecteu islandicns ; Bowerbank mentions it on Pecfeu operations, and Lambe has it from the American coast on Pecteu tenuicostatus. Levinsen mentions it from Denmark on Mytilus modiolus and Cyprina islaudica. As rather thin, irregular incrustations it is found on barnacles, Bryozoa, worm- tubes, and Lamiuaria-roots. The largest specimen in hand, which is not attached, has a greatest breadth of ii5 mm and a height of 90 mm ; most of the specimens are not so large and especially not so high; a middle-large one, growing on a Pecteu, is 75 mm broad and ca. 25 mm high. The smallest speci- men in hand forms a small crust on a barnacle, it has a greatest extent of 9 mm and is only o'5 mm thick. The consistency is of middle hardness, it is only little elastic and rather fragile. The colour (in spirit) is most frequently light yellowish; in the fresh specimens it is described as yellow to orange. The surface may be somewhat varying; it may sometimes be quite even and smooth, but most fre- quently it is more or less, often highly grooved, and the grooves are separated by winding and wrin- kling walls. These walls are formed by the parts of tissue separating the canals; these canals are present in large numbers, they run very close to each other, and are most frequently directed towards the surface. Although the dermal membrane, as will be mentioned later on, is supported by the projecting spicuia-bundles, the surface is nevertheless almost smooth, the spicules projecting so little, that they are only to be observed by means of a highly magnifying lens. When the walls are more !24 POR1FERA. II. compressed and have sharp edges, these edges, however, are most frequently finely spined, which is owing to the skeleton below. The dermal membrane is a rather thin, transparent film. It is supported by bundles of dermal spicules projecting in a fan-shaped way. These spicula bundles, however, are frequently not perpendicularly erect, but more or less, often highly recumbent. Of spicules the mem- brane otherwise has only microscleres. In different individuals, or in different places of one individual, it may have a somewhat different appearance; in more compact individuals with not especially large canals (perhaps more contracted individuals), or in places of the individual showing such a condition, the skin is rather smooth, and the projecting spicula-bundles are here close-set and rather perpendicular. Where the surface is more grooved and the membrane stretched over the grooves, the structure is some- what different, as there are here large parts of the membrane with no skeleton immediately below them, from which the bundles ma}- arise. Then the bundles issuing in a fan-shaped way from the edge reach into the membrane, and are quite, or almost quite recumbent in it, and in the middle part of it, where the bundles do not reach, scattered horizontal spicules are further found. In other places the structure is again somewhat different, fibres running from the skeleton under the parts of the membrane stretched over the grooves, from which fibres fan-shaped bundles project and pass into the membrane where they are more or less horizontal. This latter structure gives to the dermal membrane a peculiar appearance, as the parts of the membrane that are stretched over the canals or the subdermal cavities and, on account of the cavities below, appear as dark areas, are again subdivided by the mentioned fibres, which form a reticulation, in the meshes of which the pores are then situated. The pores are found in the dermal skeleton in the areas formed by the skeleton; they may be present every where, but are seen especially numerous and close-lying in the parts of the dermal membrane situated over the subdermal cavities, which parts are here often reduced to a sieve. They are round or oval and of sizes from quite small ones to cri5 mm . Oscula are found scattered in rather slight numbers; as men- tioned above, they are sometimes found on the top of conical projections, but these projections are often quite low or quite wanting. In a few cases the conical projections are not separated, but form a continuous wall with several oscula placed in the edge. This structure is illustrated by Bower- bank's figure PI. XLIV, 7. In the largest specimen in hand eleven oscula are found. The appear- ance of the oscula may be somewhat varying; in the more compact forms with even surface the osculum is a regular round or oval aperture definitely bounded by the skin, which rises sometimes to a sharp edge round the aperture. Here the oscula are most frequently small, and were measured down to i mm or less. In individuals with highly grooved surface, on the other hand, the edge of the oscula becomes often irregularly indented, so that the aperture is somewhat lobed. It is this structure which causes Johnston to use the expression: ^oscula obscure, substellated , presumably the dermal membrane has also been wanting to a great extent, and then oscula are little marked compared to the openings of the inhalent canals. When oscula are of the last-mentioned structure, they are generally rather large, and they were measured up to a diameter of io mm . The skeleton. The dermal skeleton consists, as already mentioned, of perpendicular or more or less recumbent bundles of dermal spicules, which pass off from the main skeleton and support the dermal membrane, and bend as fibres under and into the parts of the membrane stretched over the subdermal cavities. Generally the question is only of bundles; but sometimes, in certain places of the PORIFERA. II. J 35 sponge, they are lengthened more inward, so as to become short fibres passing out and ending in the dermal membrane. In the ridges of the surface that are more compressed and sharp-edged, the dermal skeleton is often much suppressed, and the main skeleton may continue quite out and give rise to the mentioned small spines. The main skeleton consists typically of triangular or, more properly, tetra- hedral meshes, the sides of which have the length of a spicule and are formed of from one to five or six spicules. It may, however, be somewhat differently constructed in different individuals. Thus more or less marked fibres occur not rarely in larger or smaller numbers; they run especially in the direction towards the surface. When these fibres occur in larger numbers, some quadrangular meshes may be formed here and there, but a regular, quadrangular net of meshes is not formed. The longer fibres are generally a little thicker than the others. In other individuals the skeleton is much less regular and is not formed of so distinct triangular meshes, and then it is upon the whole of a more diffuse character. In the membrane coating the canals only microscleres are found. Spongin is found in the nodes of the skeleton, but it is only to be observed with much difficulty, as it is quite white and clear, and only a minimal amount is present. Spietda: a. Megasclera. i. The skeletal spicules are acanthostyli, straight or slightly curved, most frequently with the curve near the upper end; the point is middle long or rather short. The spiuulation may be somewhat varying, but is generally rather scattered; the spines are not rarely gathered a little more densely at the upper end; only a short part of the point shows no spines. The styli vary rather much in size, not, however, in one individual, but in different individuals, whereas the variation in one individual is most frequently only slight. The length varies altogether from 0-19 — o - 35 mm ; in the single individuals may be found for instance: 0-19— o - 22 mm , o - 2i — o-268 mm , 0-238 — o-298 ram , and o'28— o - 35 mm . The thickness, which is only partly proportionate to the length, varies alto- gether between crooS and o-oi5 mm . Finer, down to quite fine styli which are certainly developmental forms, occur in most individuals scattered in the tissue. They have about the full length, and their point is long and fine. Among the finest of them some were smooth, but otherwise traces of spinu- lation occur early. In the fine forms the spines are small and especially low, so that these forms may get an irregular, knotty appearance. In an individual with needles of the greatest lengths given above, the fine developmental forms were measured, for instance, to 0'29 mm with a thickness of o-oo28 mm ; the very finest one observed was o - ooio mm thick, and ca. o - i7 ram long; in this needle no trace of spinu- lation was seen. From the finest stages all transitional forms are found to the fully developed needles. 2. The dermal spicules are tornota; they are straight, or at most quite slightly, irregularly curved. They are cylindrical and most frequently slightly fusiform. The ends are short pointed; often a slight constriction is found below the end; the ends are slightly spinulous, only in a few cases smooth or almost smooth. It is to be remarked that the ends of the tornota are not always quite equal, but one end is frequently a little thinner than the other. Their length varies in a similar way as that of the styli, altogether it is between 017 and o - 26 mm , but in individual specimens it was measured, for instance, to 0-17 — o-2o mm , 0-19 — o-22 mm , and 0-21 — o - 26 mm . The thickness is 0-0057 — o-oi mm . Only very few finer forms were seen, and none very fine. Mierosclcra; these are of three forms, three-toothed isancorse spatuliferse of two forms, and sigmata. 1. The large an corse have a slightly curved shaft, and in either end three lanceolate teeth ; in both ends a rather narrow ala is found on either side of the 136 PORIFERA. II. shaft; the ake are most frequently a little longer than the teeth. The teeth are directed slightly out- ward. The length varies altogether between ca. 0-038 and o-07i mm ; it ma)' vary somewhat in the single individual, not, however, so much. Thus in a specimen with the smallest ancorse the greatest length was o-043' nm , and in a specimen with large ancorse the smallest form was o-059™ m long. The greatest breadth of the ancorse from one lateral tooth to the other is about 0-014— o-025 mm . Besides the length also the dimensions of the different parts may vary; thus alse and tooth may be comparatively longer or shorter, and the free middle part of the shaft may, according to this variation, be from one third to one fifth of the whole length. Of this ancora a few half-developed stages were seen, in which only beginnings of the teeth and fakes were present. — This ancora showed frequently, at all events in many individuals, many different deformities. It has been mentioned that the ancorse may vary some- what with regard to the length of the teeth; also the breadth of the teeth may vary, and they may be very narrow. Then they may be straight cut off at the end, and here they have very often an incision, so that they become more or less deeply split. Further the alse may separate more or less from the shaft, and each form a tooth, or they may coalesce so as to form one tooth, so that we get four or five teeth, each directed its own way. The teeth or tooth-like structures which in the mentioned cases replace the alse, appear, as far as I have been able to observe, when they are quite separated from the shaft, to be upon the whole of the same construction as the genuine teeth, but this is only rarely the case, as most frequently the)- are only partly separated from the shaft. All these deformities, for as such they must be regarded, show the peculiarity that they are always symmetrical, occurring in quite the same way in both ends. Finally the ancorse are often somewhat twisted. 2. The small ancorse have a comparatively more curved shaft than the large ones, and further the teeth are less directed forward, so that a line through the two middle teeth would be straight or almost straight. In either end there are three leaf-shaped teeth, which are most narrow at the base, and an ala on either side of the shaft. Teeth and alse are comparatively long, so that the ends of the teeth approach each other, and the free middle part of the shaft is quite short, only ca. one eighth of the whole length, so that there is often only seen an incision between the alse. The length of these ancorse varies from 0-017 — o-o28 m,n , but the dimensions of the different parts remain about the same. The breadth is ca. 0-0057 — o-oo85 mm . Also of this ancora a few developmental forms were seen. The two forms of ancorse are sharply separated, both by their sizes and by the characteristic form of the small ancora. A few ancorse may be found, however, that seem with regard to form and size to be intermediate between the two groups, yet with regard to form the)' approach always more nearly to the large ones. 3. Sigmata are more or less contort, up to one fourth of a turning. They are exceedingly varying in length, from 0-024— o-075 rom . The variation, however, is not so great in all individuals; thus the upper limit was measured in some specimens to o-o64 mm , and in others to only o-04 mm , the lower limit, on the other hand, seems to be about the same. The thickness varies alto- gether from o-ooi— o-O05 mm , according to the size. The middle sizes of the sigmata occur very sparingly, and therefore the impression is frequently imparted that sigmata form two groups; this fact is espe- cially conspicuous in the individuals in which sigmata reach the largest size, while the difference is smaller in individuals in which sigmata do not reach any considerable size. When they are divided in two groups, the fact is that the small sigmata may only vary a little in size, while the large ones PORIFERA. II 137 vary somewhat more. All forms of microsclera occur throughout the sponge; the}' are also found in the skin, and especially in large numbers in the membranes of the canals. Embryos. In most individuals embryos were found; they were present in large numbers and were lying rather close in the tissue. The embryos are globular, and their average size is 03 — o'5 mm Of spicules only megasclera were found in almost all the examined specimens. These megasclera are finely knotty, straight tylostyli; in the fine ones the head is most frequently found a little below the end, while in the thicker ones the end itself is swollen. Their length was measured from 0-045 U P to o-i3 mm by a thickness of o - ooi— o - 0O5 n "". Thus these needles are skeletal spicules, which accordingly are the earliest occurring ones, whereas no dermal spicules were found. In a few embryos, in which the stvli were of the largest sizes, also microscleres were found, that is to say developmental forms of the aucorse; these forms were measured to a greatest length of o-oaS'"" 1 , but their form indicated that the) belonged to the large form. Spicules were already present in all the examined embryos. Locality: We have a rather copious material of the species. Station 31, 66° 35' Lat N., 55 54' Long. W., depth 88 fathoms; station 34, 65 c 17' Lat. N., 54 17' Long. W., depth 55 fathoms; station 127, 66° 33' Lat. N., 20 05' Long. W., depth 44 fathoms; Holstensborg (Bergendal); Egedesminde (Traustedt); Jakobshavn (assistant Olsen); Jan Mayen, depth 55 fathoms (the Amdrup Expedition 1900); the Bay of Skagestrand, depth 33 fathoms (Ditlevseu); east of Nolso, depth ca. 30 fathoms, at the northern end of Nolso, depth ca. 100 fathoms (Th. Mortensen). The localities are situated off West-Greenland, north of Iceland, off Jan Mayen, and off the Faroe Islands. Geogr. distr. The species is hitherto known from the coast of Jan Mayen (Marenzeller); from the Orkneys, the Shetland Islands, the Hebrides, and the coasts of Great Britain and Ireland (Bower- bank); the Sound (Levinsen); the coasts of France, at the Channel and at the Atlantic, for instance the Bay of Biscay, at depths of ca. 96, 133, and 206 fathoms (the «Caudan , Topsent), and finally from the Gulf of St. Lawrence (Lambe). In the seas in question it is thus distributed from 71 to 45 Lat. N. It is chiefly a shallow water- and shore-species, and the greatest depth, from which it is known, I suppose to be stations 19 and 32 of the < Caudan in the Bay of Biscay with a depth of ca. 206 fathoms (400 metres). Remarks: I have been able to determine this species with certainty, as I have examined a specimen sent by the Rev. Mr. Norman; this specimen showed distinctly the spined ends of the tornota. As will have been seen from the description, the species may be somewhat varying, especially with regard to the size of the spicules, and it seems even to be able to vary still more than shown by my material; thus Lambe I.e. gives the lower limit of the styli to o-i2 mm and of the tornota to o-i4 mm , but here, perhaps, developmental forms are included. The species has surely often been described under different names. As mentioned by Levinsen 1. c, it is thus this species O. Schmidt has determined as fimbriata Bow., and, in Spong. des atlant Gebiet. 1. c, quoted from Denmark and Greenland, which fact is shown by the specimens in the museum at Copenhagen. I suppose that it may also be regarded as a certain fact that M. barentsi Vosm. 1. c. is identical with the present species, and this seems also to hold good with regard to the M. barentsi mentioned by Lambe (Trans, of the Roy. Soc. of Canada, 1894, XII, Sect. IV, 121, PI. II, figs. 9, 9 a— c). I also think that Hastatus Robertson/' Frstdt., 1. c, is the same species. With regard to both species the descriptions agree exactly with incrnstans. Of the two varieties of incrnstans, typica and viscosa, mentioned by Topsent (Arch, de zool. exp. et gen. The Ingolf-Expedition VI. 2. l8 133 PORIFERA. II. Ser. 2, V, bis, suppl. 118), on tlie other hand, at all events only the former is incrustans; the tornote figured by Topsent has smooth ends, but perhaps the spines, which may be very fine, have been over- looked; the tornote with cleft ends figured for var. viscosa, on the contrary, belongs, no doubt, to the following species. Finally Topsent (Resultats du Voyage du S. Y. Belgica, 17) describes a Deiidoryx incrustans var. australis; on account of the sizes of the megascleres, the styli are 0-5 — o - 6 mm , and the tornotes o'32 mm , I think it more probable that it is an independent species. - - The Halichondria incru- stans var. with angulated anchorate and smooth acuate from the west coast of Florida mentioned by Carter (Proceed, of the Acad, of nat. Sc. of Philadelphia 1884, 205) cannot be the present species, but must belong somewhere else. 2. M. rosacea Lieberk. PI. IV, Fig. 8. PI. XIV, Fig. 4 a— h. 1859. Halichondria rosacea Lieberkiihn, Arch, fur Anat. 521, Tab. XI, Fig. 2. 1862. Myxilla rosacea O. Schmidt, Spong. des adriat. Meer. 71. 1864. Myxilla tridens O. Schmidt, ibid., Suppl. I, 36, Tab. IV, Fig. 5 a — d. 1864. Myxilla Espcrii O. Schmidt, ibid., 36, foot-note. 1880. Myxilla rosacea Vosmaer, Notes from the Leyden Mus. II, 123, 1. 1882. Graeffe, Uebers. d. Seethierf. des. Golf, von Triest, Arbeiten aus dem zool. Inst. Wieu IV, 6. 1888. Dendoryx incrustans var. viscosa Topsent, Arch, de Zool. exp. et gen. Ser. 2, V, bis, suppl. 119, PI. VI, fig. 16, b. 1890. Dendoryx incrustans var. viscosa Topsent, Mem. de la Soc. zool. de Fr. 201. 1892. - — Topsent, Resultats des Campagn. scient. du Prince de Monaco, Fasc. II, 98. Intrusting (sometimes forming free branches). The surface grooved, slightly shaggy. The dermal membrane thin, supported by penicillate bundles of dermal spicules. The skeleton a polyspicular reticu- lation, forming partly triangular meshes, partly quadrangular, or irregular ones. Spicnla: megasclera : the skeletal spicules acanthosfyli, dispersedly spined 0-178 — 0-24.""", the dermal spicules tornota, most fre- quently with three-pointed ends 0-/78 — 0-22"""; microsclcra of two forms, ancorce spahiliferce 0-0/57—0-05""". sign lata o-o/8 — o-oj2""". The specimens in hand of this species occur as thicker or thinner incrustations, especially on Hydroids, and a few ones on erect Bryozoa. In the material it is found growing on Diphasia abietina, Halecium sp., and Lafoea sp., and of Bryozoa on Cellaria fistulosa and Bugula murrayana. As the form of the sponge chiefly follows the substratum, it becomes most frequently longish and rather irregular. It always grows all round the Hydroid. Independent free branches seem, however, also to be found, as the material includes some such branches, but they are torn off. The largest specimen in hand has a greatest extent of ca. 57""" and a breadth of about 25 mm ; the thickness of the incrustation is scarcely more than 5 mm . The mentioned free branches are more or less compressed, and have a greatest breadth of 14™™, the longest one is 40'"'" long. The consistency is rather firm and somewhat PORIFERA. II. *39 elastic. The colour (in spirit) is in some specimens whitish yellow to grayish yellow, but not rarely it is light brown or reddish brown. Lieberkiihn states that the fresh sponge is of a dirt}' rose-red colour, and Schmidt says that it is yellowish or dirtily rose-red. The surface is much and irregularly grooved, being, as in the preceding species, provided with knobs or sinuous ridges separating inter- jacent grooves; otherwise it is quite slightly shaggy from projecting spicules. The dermal membrane is a thin film supported by projecting bundles of dermal spicules spread in a penicillate way; other- wise it has no skeleton. The pores are situated in the areas formed by the dermal skeleton; they are especiallv close-lying over the larger subdermal cavities, where they most frequently reduce the mem- brane to a network. They are round or oval, and their size is o - oi8 — o - ii' mn . Distinct oscula were not seen. The skeleton. The dermal skeleton consists, as in the preceding species, of bundles of tornota which project from the main skeleton, being spread in a penicillate way, and support and pierce the dermal membrane. The bundles have generally a length of only about one spicule; only where large subdermal cavities are found, short fibres are formed of the tornota, which fibres pass into the mem- brane stretched over the cavity, and branch, continually sending fan-shaped bundles up through the membrane. The bundles are most frequently rather erect, but may in places be more or less recumbent. Besides in the dermal skeleton tornota are also found in the membranes of, at all events, the larger canals. The main skeleton is a rather irregular, polyspicular network. It forms partly tetrahedral, partly more or less cubic or quite irregular meshes. Some longer fibres are found, especially running towards the surface. In the mentioned free branches rather long fibres are formed running lengthways of the branches. The fibres or spicula-bundles may have up to ca. six spicules alongside. As in the preceding species spongin is found in the nodes of the skeleton, but it is only to be observed with difficult}-, as it is only present in small amount, and is quite white and clear. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli, the}' are most frequently slightly and evenly curved throughout their length, only more rarely they are straight; the point is even and middle long, but may vary a little in length. The spines are much scattered and rather small; only at the upper end the}' are a little more close-set, and are also here a little larger; the point is smooth for a longer or shorter space. The length varies from 0-178 — o - 24 mm , and the thickness from 0-008 — d-oii"" 11 . Some developmental forms were found, they were of different thickness, the finest ones were measured to ca. 0'0007 mm , and had a length of about cri4 mm . Forms of a thickness of about Q.QQjmm -were slightly knotty or almost smooth, whereas forms a little thicker were distinctly spined. The developmental forms show a little distinct head-swelling, which is more distinct, the finer the needle is. 2. The dermal spicules are tornota; they are straight or slightly curved in different ways and slightly fusiform. Their ends are peculiarly formed; they taper only a little, and then they are abruptly cut off, the edge of the end thus cut off carries some small points, most frequently, as far as was to be seen, to a number of three. Sometimes the outer part of the tornote is quite slightly swollen. Most frequently their ends are not quite equal, one being a little thinner than the other. Their length varies from 0-178 — o-22 mm , and the thickness from 0004— o-oo8 mm . Developmental forms were seen in small numbers; in conformity to the development they show the greater difference between the two ends, the younger they are. b. Microsclera are of two forms, tridentate isancorse unguiferae and sigmata. 1. The an cor a? have an evenly curved shaft; at either end they have three 18* 140 PORIFERA. II. teeth, and 011 either side a narrow ala. The alae continue along the shaft, and in the middle they are connected by a quite narrow rim; thus there is no free middle part of the shaft, but only an incision in the rim running on either side. The ancorse are very varying in size, their length is between 0-0157 and o - 05 mm , and the breadth is proportionately 0-004— o-oi8 mm . The larger ancorse are most predominant. Developmental forms in different stages were seen. 2. Sigma ta are of the common form and contort in different degrees; their size is rather varying, the length from o - oi8 — o-032 nira , and the thickness from ca. o-ooii — o-oo2 mm . Both forms of microsclera occur through the whole sponge and in no small numbers in the dermal membrane. Remarks: Of this species I have for comparison had a fragment of one of Schmidt's type specimens sent to me by Dr. Mark tanner-Turneretscher, and so I have been able to identify my species with certainty. It is also quite in conformity to Lieberkiihn's description and figures I.e.; especiallv the figure of the acanthostyli is exceedingly characteristic. On the other hand neither Liebe