THE DANISH INGOLF-EXPEDITION. — ^^ ^^ ^^^^ i-q — __ _D s=l 1-0 BL/WHOI Willi r-q t-n a a ^^— — D m ; □ r D VOL. VI, PART 3. CONTENTS: WILL. LUNDBECK: DESM ACIDO NID^l (PARS.). PUBLISHED AT THE COST OF THE GOVERNMENT BY THE DIRECTION OF THE ZOOLOGICAL MUSEUM OF THE UNIVERSITY. •c^»,2* :* I COPENHAGEN. H. HAGERUP. PRINTED BY BIANCO I. UNO. I9IO. THE DANISH INGOLF-EXPEDITION. VOLUME VI. 3. PORIFERA. (PART III.) DESMACIDONID^ (PARS.). BY WILL. LUNDBECK. WITH ii PLATES. ->^:r«f<- COPENHAGEN. PRINTED BY BIANCO LUNO. 191O. Ready from the Press Avril the Ist 19 10. CONTENTS. Desmacidonldce. Page Desmacidonidse I Mycalinae I Myxillese I Tedania i — suctoria O. Schmidt I Histoderma 7 appendiculatum Cart 7 physa O. Schmidt 11 Histodermella 13 Ingolfi n. sp 14 — coriacea n. sp 16 Inflatella 18 — pellicula O. Schmidt 1 — viridis Tops 20, Cornulum 22 — textile Cart. 22 Grayella 29, — pyrula Cart 30. — gelida n. sp 34. — carnosa Tops 36 Ectyoninae 39 Hymedesmia 39 Koehleri Tops 42 lacera n. sp 44. — storea n. sp 45 lamina n. sp 46 — mollis n. sp 47 curvichela n. sp 48, rugosa n. sp 50 — splenium n. sp 51 tenuicula n. sp 52 — similis n. sp 53 nummulus n. sp 55 dubia n. sp 56 stylata n. sp 57 verrucosa n. sp 58 — procumbens u. sp 60. — perforata n. sp 61 — clavigera n. sp 62 platychela n. sp 63, — basispinosa n. sp 64 Page Hymedesmia longistylus n. sp 66. — occulta Bow 67 simillima n. sp 69 baculifera Tops 71 levis n. sp 73 bractea n. sp 74 laevistylus n. sp 74. — Bowerbanki n. sp 75 — truncata n. sp 77 — latrunculioides n. sp 78 — irregularis n. sp 80. — proxima n. sp 81 — crux O. Schmidt 83 — aenigma n. sp 84 filifera O. Schmidt 86 — grandis n. sp 88, — digitata n. sp 90, trichoma n. sp 91 — macrosigma n. sp 92. — pugio n. sp 94. consanguinea n. sp 95 — planca n. sp 96, cultrisigma n. sp 97 — mucronata Tops 98, — tenuisigma n. sp 100. — Dujardinii Bow 101 primitiva n. sp 104 longurius n. sp 105 aequata n. sp 106 — dermata n. sp 107 — tornotata n. sp 109 mucronella n. sp no. Table of the species of Hymedesmia 112 Hytnenancora 116 — interjecta n. sp 117 — conjungens n. sp 1 1 duplicata n. sp 119 tenuisclera n. sp 12 r Leptolabis 122 — assimilis n. sp 122 4187° Porifera. III. By William Lundbeck. (Fam. III. Desmacidonidae.) (Subfam. i. Mycalinae) (Group 2. Myxilleae.) Tedania Gray. Of various shape, incrusting, massive, erect and leaf- or cup-shaped, or cylindrical, or finally more or less digitate and branched. The skeleton a more or less diffuse reticulation, generally inultt- spic?/lar, more rarely partly or quite unispicular. Spongin generally (or always) present, as a rule to a slight degree, sometimes more richly. The dermal skeleton as a rule formed of erect bundles of dermal spicules, sometimes also spicules lying horizontally in the dermis ; it is sometimes strongly devel- oped, sometimes weaker, with relatively Arc spicules. Oscula scattered, sometimes on the apex of tubes or papilla- ; pores scattered or on the apex of papilla- or otherwise definitely localised. Spicula: mega- sclera: the skeletal spicules are smooth styli, the dermal spicules diac final, fylofa, tornota or strongyla, sometimes with slightly spined ends; microsclera only one form, rhaphides ?uifh unequal ends, finely spinulous, in dragmata or scattered. i. T. suctoria O. Schmidt. PI. I, Figs. 1 — 5, PL IV, Fig. 1. 1870. Tedania suctoria O. Schmidt, Grundziige einer Spongienf. des atlant. Gebiet. 43, Tab. V, Fig. 11. 1875. Tedania increseens O. Schmidt, Jahresb. d. Comm. zur wiss. Unters. deutsch. Meere in Kiel fur 1872-73, 115. 1882. Tedania suctoria, Vosmaer, Niederl. Arch. f. Zool. Suppl. Band I, 42, PI. I, fig. 24, PI. Ill, figs. 83—88. 1885. — — , Vosmaer, Bijdr. tot. de Dierk. i2te Afl. 3die Gedeelt. 22. 1892. Tedania conuligera Topsent, Resultats des camp. sc. du Prince de Monaco, Fasc. II, 79, PI. I, fig. 16. 1903. Tedania increseens. Thiele, Arch, fur Xaturgesch. 1903, I, 380. Taf. XXI, Fig. 9. 1904. Tedania suctoria. Topsent, 1. c. Fasc. XXV, 176. 1909. — — , Lundbeck, Meddel. om Gronland, XXIX, 443. Incrusting. massive, or more erect and sometimes somewhat branched. Surface more or less richly beset with papilhr and diffusely hispid. The dermal membrane somewhat solid, its skeleton -weakly developed, consisting of bundles of dermal spicules, partly erect, partly more horizontal; also scattered The Ingolt-Expedition. VI. 3. J PORIFERA. III. spicules. Oscula few, lying on special papillce, pores on the summit of other papillce. The skeleton a mainly polyspicular. diffuse and irregular reticulation. Spicula: mcgasclcra: the skeletal spicules styli 0-j0 — o-68""". the dermal spicules tylota 0-25— 0-47""" : microsclera one form, finely spinulous rhaphides •with unequal ends trojjj—O-ju""". Of this species we have a very rich material from the whole Ingolf territory. The individuals may have a very different aspect, but as a rule they are characterized by having a greater or smaller number of wart-shaped papillae. In the typical and fully developed shape the species is massive, more or less roundish, lumpy and in greater or smaller extent attached to a substratum. From this roundish shape the species may show many variations, it may be elongated and assume a somewhat erect shape, and it may be club-shaped, lobate, compressed or more or less branched. The latter shape is no doubt due however, at all events partly, to the fact, that it incrusts, or originally has incrusted, branched Hydroids or Algse, but in this case it seems to be able to continue its growth out in free, branched forms. The smallest and youngest specimens are incrusting and from this crust-shaped origin it may then by and by grow up to the massive shape, but it may also persevere as a crust and as such reach a considerable extent. In our material it is found growing on stones, various Bryozoa, worm- tubes, Alga; e. g. Ptilota plumosa, the specimen on this is branched, and finally on a crab. The largest specimen, which is of an elongated shape, has a length of about 40 mm; a massive, tuberous specimen is 30mm in diameter; the incrusting specimens are generally small, but may, as said, reach a greater extent, up to 25°"" with a thickness not much over imm. Topseut mentions and figures (1. c.) larger specimens, up to an extent of 9C'IK, of typical massive shape. The colour (in spirit) is yellow or whitish yellow. The consistency is of medium firmness and somewhat elastic. The surface is more or less densely beset with papillae, otherwise it is, when examined with a lens, somewhat diffusely- hispid. In the larger, massive specimens the papillae are generally present in great numbers, and the same is the case with the larger crusts; in the small incrustations the papillae may be few or indistinct. The dermal membrane is a very solid and easily separable membrane; outermost it shows a thin, film- like layer, which under the microscope is seen to be curled or folded. It would seem that this layer in the living sponge is adhesive, as it generally shows adherent foreign particles such as diatoms in oreat multitude. Oscula and pores: as mentioned the surface is more or less richly beset with papilla; which are specially well developed in the larger specimens, while they are less developed in the small specimens. The papillae are conical in their lower part, the upper part being cylindrical. They are seen from quite small warts up to a length of 4mm; they are compressed and have a breadth up to i'5 mm. These papillae must be supposed to he partly oscular- and partly pore-papillae, the fact is, that they show some difference. Some few of them are simply hollow and show an opening in the summit, their wall is thin and supported by dermal spicules which are more or less distinctly arranged as longitudinal bands; these papillae must accordingly be taken to be oscular-papillae. By far the most of the papillae have another structure; they are hollow like the oscular-papillae, but from the wall spi- cula fibres stretch into the lumen; these fibres may be branched upwards and terminate in the upper surface of the papillae, which is thus supported by a number of spicular pillars. All the spicules in these fibres are dermal spicules. The papillae show no opening at the summit. These papillae must be supposed to be pore-papillae, and probably the pores are found at their ends. The pores I have PORIFERA. III. not seen, but as the papillae are nearly always somewhat contracted, it was also not to be expected, that the pores should be visible. The two kinds of papillae are often recognisable already from their outer shape, the oscular papillae being somewhat evenly couically pointed, while the pore-papillae are more cylindrical in their outer part and have a stubby or cut end. Often, however, the papillae are so strongly contracted, that it is not possible to distinguish them from each other so directly. In the dermal membrane outside the papillae no pores were found. The structure mentioned of the papillae has not been described hitherto, only Schmidt has some remarks about it, but he takes them all to be oscula. For the rest he speaks about the peculiarity of the dermal membrane, remarking that it consists of: "einer ausseren sarcodeartigen und einer inneren festen membranosen Schicht". From his description of the papillae it is seen, that it is a pore-papilla he has examined, which are also by far the most numerous; the fact is that he says: "Das Ende der Warzchen ist etwas verdickt, der Gipfel scheinbar geschlossen, alleiu eine massige Vergrosserung zeigt, dass der Hauptcanal in einer Anzahl Haarcanalchen sich nach aussen off net". The "Haarcaualchen" Schmidt has seen are no doubt the inner cavity divided by the fibres, and his description is otherwise in the main correct, only he takes the papilla to be an oscular-papilla. The skeleton. The dermal skeleton; the skeleton formed by the dermal spicules is not much developed, it consists of larger or smaller bundles of dermal spicules lying in the membrane, partly horizontally, partly more or less erect in the somewhat thick dermis; besides the bundles more scattered and single spicules may also occur, but they are on the whole scarce, and large parts of the membrane may be seen without dermal spicules. At the base of the papillae they are present in greater numbers, and from here they stretch out in the wall of the papilla and form the skeleton of the papilla as mentioned above. The main skeleton is a rather diffuse and irregular, multispicular reticulation in which primary and secondary fibres cannot be discerned; also single spicules are in many places seen to contribute to the skeleton. In the points of union is seen a distinct and rather rich amount of spongiu which may also sometimes be seen to continue along the fibres. Splcula: a. Megasclera. i. The skeletal spicules are styli, they have an even, generally slight curve, lying nearest to the rounded end. The apex may be somewhat different, partly in the same individual, but especially in different individuals; it is generally of moderate length, but it mas- be both shorter and longer, and it may be bounded by straight or curved lines; finally it may be marked off in different ways; in a single specimen the point is often rounded and thus stubby. The length of the styles may vary considerably, yet generally not much in the single individuals, but on the other hand in different individuals; in all it is in the species between 030 and 0'68'nm, but only when the sizes measured for all individuals are taken into consideration; as the common lengths may be given C42 — o-53m,n. The diameter is on the whole o-oo7mm — o-oi4'm", but here also some difference is present, in single specimens not reaching beyond con — O'oi2mm. 2. The dermal spicules are tylota, they are generally straight, sometimes slightly curved. They have a distinct, but often rather elongated swelling at each end as a rule passing evenly into the shaft; this latter is sometimes somewhat poly- tylote. Also with regard to this spicule the length varies somewhat from individual to individual and follows herein the variation of the styles; the length lies in all between 0-25 and 04.7 m,n, generally it is 0-32 — 0-41 ,nm. The diameter is about 0-003— o-oo6mm, but sometimes does not reach the latter size. PORIFERA. III. The fully developed tylotes have about equal ends, but single developmental stages were seen, distinctly showing, that the tylote originally is monaetinal. b. Microsclera; there is only one form, rh aphides; they have the special shape which is probably common to all the rhaphides in the species of Tcdania. One end is short and curiously, obliquely pointed, while the other end tapers into a long, very fine apex; otherwise they are spinulous which under a low magnification is only seen as an indistinct fine creuu- lation; under a greater magnifying power it is on the contrary seen, that they are distinctly spined, the spines being dentiform and strongly compressed in the longitudinal direction; the smaller rhaphides are the relatively most strongly spined (PI. IV fig. i c). The length varies to a very high degree in the single individual, and also somewhat from individual to individual; it is in all 0-053— 0-50™™, gen- erally it is o-o6o— 0-32 mm. Whether these different sizes are developmental stages it is difficult to de- cide, but it is most probable, that they are, at all events for a great part, fully developed forms. To be sure all intermediate sizes are seen between the given sizes, but certain sizes seem to predominate and I am inclined to think, that three different, independent sizes are present (PI. IV fig. 1 c). When intermediate sizes are found between them, this may be due partly to the variation of the single sizes, but perhaps also partly to the fact, that a number of developmental stages are present among them. The thickness is, in relation to the length, about o-ooio— 0-0028 mm; the latter thickness was only reached by the longest rhaphides and consequently not found in all individuals. The rhaphides occur in great multitude both in the dermis, and otherwise in the tissue of the sponge; they occur both in dragmata and singly and scattered; I have however only seen the large rhaphides in drag- mata; all rhaphides in a bundle seem to have the equal ends turned in the same direction. To show the variation in the length of the different spicules in various individuals and how the lengths with regard to all three forms of spicules are in the main related to each other I may give some measurements: Styles tylotes rhapides 0-30— o'35mm 0-25— 0-32 mm °'°55 — °'25 '"'" (small specimen). 0-35— 0-47 m,n 0-27— 0-33 mm 0-053— 0-29 mm 0-44 — o-49mm 0-31 — o-38mm 0-064— o-32omm 0-43 — 0-53 mra 0-35— 0-41 ,nm 0-064 — o'329,nm 0-51— o-68mm 0-35— 0-47 m,n 0-064— 0-50""" Remarks: As Schmidt's type-specimen is found in my material, the identification is certain. I have also examined a type-specimen of Tcdania increscens O. Schmidt, and have thus been able to decide with certainty, that this species is identical with suctoria. Thiele thinks 1. c. that increscens might be a good species, because its styles are larger than the measurements given by Schmidt for suctoria; but the variations of the spicules given above show however, that from this no character can be drawn. Tops en t himself (Rev. Suisse de Zool. IV, 1897, 454) has abolished Tcdania conuligera as identical with suctoria, and his description also shows, that this is correct. The specific characters for the species of Tcdania seem especially to lie in the shape of the dermal tylotes, and this is not astonishing, as the dermal spicules in other Myxillem are also characteristic. Besides T. suctoria I have examined T. digitata O. Schmidt, tcnuicapitata Ridl. and massa R. and D., and of these species I have examined specimens of suctoria from the whole Ingolf territory and from the Willem Barents PORIFERA. III. Expedition, and of digitata from Trieste, Senegal and the Antilles, and I have in these species found the dermal spicules characteristic and constant. T. suctoria has tylota with generally weak and elongated end-swellings, T. digitata has tylota with more or less weak end-swellings bearing some spines on the end, T. tenuicapitata has tornota, and when Ridley and Dendy say (Chall. Rep. Monaxonida, 52), that the dermal spicules in this species may also have round end-swellings, but in a foot-note declare, that such spicules were only found in one specimen, in which also toruotes occur- red, then no doubt a mistake or confusion must have taken place. Finally T. massa has dermal spi- cules which may best be termed strongyla but with a little mucro on the end, and the latter may be quite slightly swollen. The rhaphides in the species of Tedania have been somewhat differently understood; Schmidt only mentions them as "feine umspitzige Nadeln'', but does not mention, that they are spinulous; this fact is first stated by Ridley (Proc. Zool. Soc. 1881, 124) in the description of T. tenuicapitata and in the same place the author explains, that such is also the case in a couple of Bowerbank's species [aspera and rudis) and in suctoria O. Schmidt; the author speakes of it as "roughness", and says that it is distinct from "spination" or "microspination". Later the fine spiuulation of the rha- phides is mentioned by several authors as Carter, Ridley and Dendy, Lambe, Topsent, Lind- greu and Thiele. In the four species I have examined, the rhaphides are mainly of the same shape, and they are always finely spinulous in all specimens; I take it therefore as very probable that the TV^-w-rhaphides are always spinulous, and I consider it as certain, that smooth and spinulous rhaphides cannot occur in different individuals of the same species. Ridley describes originally the rhaphides in T. tenuicapitata as "roughened almost imperceptibly", but in the Chall. Report it is declared, that the authors in the specimens which they then had for examination had only found spinulation of the rhaphides in one specimen and moreover only in a spiculum which was not fully developed; I have however examined specimens of T. tenuicapitata from the Challenger Expedition and found the rha- phides spinulous; the spinulation is fine, but rather well distinguishable already by a magnifying power of 300; when the authors have seen the spinulation in a small spiculum, this is easily under- stood, as in the small rhaphides it is most distinct, and, as said above, it is also probable, that the small rhaphides are not developmental stages, but fully develojued spicules. With regard to the rha- phides in T. massa the authors say: "they often exhibit a roughening of the surface. . ."; my exami- nation of the species showed, that the rhaphides are always spinulous. About the rhaphides in T. cmn mixta, infundibuliformis and actiniiformis Ridley and Dendy do not mention whether they are spinulous or not, but as spinulation is not mentioned, it has probably not been seen; it is yet un- doubtedly present Topsent records (Rev. Suisse de Zool. IV, 1897, 454) a T. digitata and says, that he refers it to this species, though it has spinulous rhaphides, which have not been described with regard to T. digitata ; this however is not correct, as Carter already in 1886 (Ann. Mag. Xat. Hist. 5, XVII, 52) has declared, that the rhaphides in T. digitata are spinulous. Topsent is therefore of the opinion, that the rhaphides in T. digitata, and on account of the declaration of Ridley and Dendy, also in massa and tenuicapitata and moreover in suctoria, are able to vary, being either smooth or spinulous; according to what has been said above it must be considered as certain, that they are always spinulous. A statement of Dindgren (Zool. Jahrb. XI, 1898, 299) about the variation in the species of Tedania PORIFERA. III. and which is based on the statement, that: "Topsent dargethan, dass die Raphides bei dieser Art sowohl glatt als anch stachelig sein kounen", therefore loses its relevancy. Thiele describes in 1903 (Abhandl. Senckenb. nat. Gesell. XXV, 945—947, Taf. XXVIII, Fig. 12 — 15) four new species of Tedania; about one of these is stated, that it has distinctly spinulous rhaphides, with regard to two others is said respectively "ziemlich glatt" and "kaum rauh"; only about the fourth it is said, that the rhaphides are smooth; I think that a sufficient magnifying power would show, that they all have spinulous rhaphides. In 1905 the same author further describes (Zool. Jahrb. VI, 430—33, Taf. 30, Fig. 50 — 53) foiir new species; these are declared to have spinulous rhaphides, only with regard to one this is not mentioned. With regard to the forms mentioned by Baer (Arch, fur Naturgesch. 72, I, 1906, 17—19) as T. digitata varr. sansibarensis, fragilis and conica the rhaphides are only spoken of in a few words, and it is not said, that they are spinulous. Topsent describes (Bull, du Mus. d'hist. nat. 1907, 69, and Exp. Antarct. Fr. I9°3— °5i 3°) PI- V, fig. 6) a new species T. Charcot/' and mentions, that the rhaphides are spinulous; they are present in two forms, of which one is shorter than the other and has a swelling near one end, a shape already noticed by Thiele for one of his species. — Finally I may note that the two species described by Kirkpatrick (Nat. Antarct. Exp. Nat. Hist. IV, 1908, 32 — 33) variolosa and Coid- maiii, and by the author referred to Tedania, are without rhaphides. Still it must be noted, that Ridley and Dendy in the description of T. actiuiiforiiiis advance as probable the theory, that the rhaphides in this and in other species of Tedania are develop- mental stages of the dermal spicules; the special shape and the whole structure of the rhaphides, however, show with full certainty, that such cannot at all be the case, and besides the real develop- mental stages of the dermal spicules are not difficult to find. Locality: Of this species we have a very large material from the whole Ingolf territory; station 27, 640 54' Lat. N., 550 10' Long. W., depth 393 fathoms; station 34, 650 17' Lat. N., 540 17' Long.W., depth 55 fathoms; station 46, 61° 32' Eat. N., n° 36' Long. W., depth 720 fathoms; station 52, 630 57' Lat. N., 13° 32' Long. W., depth 420 fathoms; station 54, 630 08' Lat. N., 15° 40' Long. W., depth 691 fathoms; station 78, 6o° 37' Lat. N., 270 52' Long. W., depth 799 fathoms; station 87, 650 02' Lat. N., 230 56' Long. W., depth no fathoms; station 89, 640 45' Lat. N., 270 20' Long. W., depth 310 fathoms; station 94, 640 56' Lat. N., 360 19' Long. W., depth 204 fathoms; station 97, 65° 28' Lat. N, 27° 39' Long. W., depth 450 fathoms; station 127, 66° 33' Lat. N., 200 05' Long. W., depth 44 fathoms; further it has been taken in the Davis Strait, depth 100 fathoms (Th. Holm), at East Greenland, depth 100 fathoms (Ryder), Axarfjord on Iceland, depth 20 fathoms, ("Beskytteren" Otterstrom), at the East coast of Iceland, depth 38 fathoms (Horring), Borgarfjord on Iceland, depth 85 fathoms, (Hallas, the type-specimen of Schmidt), on 640 56' Lat. N., n° 48' Long. W., depth 115 fathoms, East of the Faroe Islands, depth 220 fathoms, (Ad. Jensen, the cruise of "M. Sars" 1902), 640 58' Lat. N., 120 40' Long. W., depth 70 fathoms, (the fishery investigation steamer "Thor"); South-east of Nolso, depth about 70 fathoms, (Th. Mortensen), between the Faroe Islands and Shetland Islands, depth 255 fathoms (Wandel); in all about 25 larger and smaller speci- mens. The localities are situated in the Davis Strait, the Denmark Strait, North, East and South of Iceland, between Iceland and the Faroe Islands, at the latter and between these and the Shetland Islands. Geogr. dislr. The species has earlier been taken South-west of Bukenfjord, Norway, depth 106 fathoms (Schmidt), the Barents Sea, depths 112, 128 and 180 fathoms ("Willem Barent"), off New- PORIFERA. III. foimdland, 460 50' Lat. N., 500 12' Long. W., depth 82 fathoms and at the Azores in depths of 318 and 664 fathoms (Topsent). The species is thus distributed between 740 36' and 380 35' Lat N. and between 36° Long. E. and 56° Long. W. The bathymetrical range varies somewhat greatly, from 20 fathoms (Axarfjord, Iceland) to 799 fathoms (station 78, on the eastern slope of the Reykjanaes Ridge). Histoderma Cart. Sponges of more or less bladder-like consistence; the shape globular or roundish in the free, not attached forms, more flattened in the attached forms. The body provided with somewhat long tubular fistulm, or with shorter or longer papillce. An outer, solid dermal layer present, furnished with a skel- eton of close-lying spicules. The skeleton of the inner body formed of partly regularly arranged, thin fibres, not forming a reticulation, or of more scattered spicules. Spongin not present. Spicula: mega- sclera only of one form, the same in the dermal layer and the inner body, they are diactinal. tylota, stron- gyla or tornota, sometimes the ends are unequal, the spicules then being tylostrongyla or tylotoruata ; microsclera; the characteristic microsclera arc chelce arcuatce ; to these sigmata are generally added, and further trichodragmata may occur; the sigmata max be of one or tzvo sizes, and a peculiar small chela may occur (naiiicelligerum). 1. H. appendiculatum Cart. PI. I Figs. 6— n, PI. IV, Fig. 2. 1874. Histoderma appendiculatum Carter, Ann. Mag. Nat. Hist. 4. XIV, 220, PI. XIV, figs. 23—25, PI. XV, figs. 39 a— b. Globular or more irregularly tuberous, provided with more or less numerous, tubular fistulce; free, not attached. Surface smooth. The body surrounded by a solid, bladder-like dermal layer. Oscu/a in the apex of some of the fistulce, pores in the apex of others. The dermal skeleton formed of close-lying, tangential spicules in several layers ; the skeleton of the inner body consisting of thin fibres, running irregularly, being regular only at the surface and parallel with this; there are no transverse fibres Spicula; megasclera tylota passing by intermediate stages into unequal-ended strougyla, o-2j — o-pj"""; microsclera two forms, cliche arcuatce 0-040— 0-046""" '. sigmata o-ojy—o-ogj""". Of this curious and interesting species — the type on which Carter founded the genus — the Iugolf-Expedition has taken a somewhat rich material. The shape is in the whole as described by Carter; the sponge consists of a globular or tuberous body, from which some few shorter or longer tubular fistulce issue. The body may be nearly quite globular, which especially seems to be the case with the smaller individuals, but generally it is of a more or less irregular shape, often some- what flattened. The fistuke are, in the specimens to hand, in most cases broken off, only some single ones are whole; they are cylindrical and straight or more or less curved, the sponge thus strongly reminds one of a potato with stolons; it grows freely, without attachment. The body has in the largest speci- men a diameter of 20 mm and in the smallest of 8ram; the length of the undamaged fistulse is about 25 mi", they are of the same length in the small as in the large specimens, while on the other hand the 8 PORIEERA. III. thickness is somewhat different, from 2 to 4mm in proportion to the size of the specimen. The colour is (in spirit) yellowish white. The consistency is hard and firm, the dermal rind forming a very firm layer, the inner body on the contrary is soft; in most specimens the inner body has therefore con- tracted strongly under the influence of the alcohol and lies like a clump in one side of the firm capsule formed of the dermal layer. By exsiccation the tissue of the inner body contracts strongly, becomes hard and of a yellow colour, so that it resembles wax, just as is mentioned with regard to the tissue of the inner body in Oceanapia robusta (The Ingolf-Expedition VI, 1, Porifera, part I, 79). The surface is smooth, only showing such a slight roughness as may be caused by the spicules imbedded in the dermal layer and parallel to the surface. The sponge has outermost a very solid dermal layer of a thickness of about 0-25"™; in places it may become thicker, up to imm; it surrounds the inner body like a mail and is very easily loosened from it, and contains close-lying spicules in several layers. Pores and oscula: Carter says: "Pores and vents not distinctly seen, but probably situated at the extremities of the tubuli respectively". This is also the case, but I too cannot solve the question with full certainty, because most of the tubular appendages are broken off. The oscula are certainly situated at the end of some of the fistulae; these latter are tubular, hollow and somewhat thin-walled; a couple of them give the impression of being undamaged, and these terminate with a simple opening which in consequence should be the osculum; a couple of the fistulae terminate with a formation quite as described by Carter, it is with a conical spout, placed at the end of the fistula; whether this is possibly the normal, closed osculum I do not venture to decide. Of poriferous fistulae there is in the material only one present, a loose tube which is broken off and has a length of 20 mm; this tube shows, that the fistula; become more thin-walled outwards, and that the skeleton in the wall becomes more scattered. The end of the fistula is rounded and forms a slightly swollen knob of a length of about 2-5"'m; in this knob the skeleton of the wall is transformed and passes into the formation of a reti- culation, in the meshes of which the pores are situated (PI. I, fig. n); the pores are oval or circular, of a diameter of 0-047 — 0-17 mm. In the dermal layer on the other parts of the body no pores are found. — As mentioned the inner body is inclined to get strongly contracted in alcohol and become hard and brittle, and there is then a large hollow space inside the dermal layer. But in single cases the inner body has on the contrary preserved its original shape and consistency; it then quite fills out the cavity formed by the dermal layer. When a section is made of such a well preserved speci- men, the canal system is shown; some large canals are seen terminating in some of the tubes, and thus shown to be excurrent canals (PI. I, fig. 8) ; besides, a multitude of smaller canals are seen. The inner body lies quite loose in the cavity within the dermal rind, and it seems only to be attached at the points where the fistulae issue; thus there are extended spaces below the dermal layer. The lumen of the fistulae is not directly continued into the canals of the inner body, as there is a diaphragm present at the origin of the fistulae; this diaphragm has in some cases a circular opening in the centre, but it seemed in other cases to be quite closed. When the dermal rind is removed, the surface of the inner body is shown; this surface is then quite undamaged, and it has the netted appearance which is so often seen on the surface of species of Reniera (PL I, fig. 9); on examining a specimen which wanted the dermal layer, one might, therefore, think that it must be an entire and un- damaged sponge. The netted appearance of the surface is due to the same cause as in the species of PORIFERA. III. Reniera, being caused by the close-lying, circular openings of the incurrent canals which shine through the thin, transparent outer layer, in which there are fine pores leading to the canals. The poriferous fistulse probably do not lead into canals, but are in connection with the space below the dermal layer; perhaps it is these fistula; whose diaphragm shows no opening in the centre. The course of the water-current will then probably be: it passes in through the poriferous fistulse into the space below the dermal layer, from here through the pore-shaped openings on the surface of the inner body and into the canal system, then in due course passing into the larger canals and finally out through the oscular fistulas. The skeleton. The dermal skeleton; the outer rind is highly provided with spicules lying very closely and in several layers, parallel to the surface; the spicules are not scattered, but arranged somewhat circularly round the bases of the fistulse, as is already distinctly visible with a lens; on the inner side of the rind there are some spicules which lie singly and rectangularly to the direction of the other spicules, and thus more or less radiating in relation to the circlets. In the fistulse the ring-like arrangement of the spicules is retained, which is the cause why the fistulas are very easily broken; some fine fibres, consisting of few spicules, run lengthwise out through the fistuke, lying on the inside of the wall, and continue from the base to the end of the fistulse in longitudinal direction; these fibres do not belong to the dermal skeleton, in so far as they are not found in the dermal layer of the body, on the contrary they issue from the inner body, and they are probably of importance in attaching it, and thus it is that the inner body, as said above, is attached only at the bases of the fistulas. In the ends of the fistulse the dermal skeleton gets more scattered, and in the oscular fistulse the spicules are here irregularly scattered, crossing each other, while in the poriferous fistulse the skeleton outwards first becomes somewhat scattered, but outermost forms a reticulation. The main skeleton or the skeleton of the inner body: In the inner body some fine fibres are found, but they have no regular course and form no reticulation; they seem mainly to run in directions parallel to the surface. At the very surface of the inner body such fibres are found numerously, running just below the surface and parallel with this, and they show a definite arrangement. They run together at the bases of the fistulse and continue, as said before, out in the fistulas; as they radiate from the base of the fistuke out in the surface, they become in the larger part of this parallel with each other, but at places where the systems belonging to different fistulse meet, the fibres run in different directions. Transverse fibres are not found, and thus there is no reticulation formed. The fibres are somewhat loose, they have an average thickness of 0-05 mm, and the distance between them is generally 0-15- 0*25 mm. — It was said above, that the inner body lies loose in the cavity of the dermal layer; as the fibres mentioned continue from the fistuke inwards and form a carpentry along the surface of the inner body, this latter is in reality kept in its place by this carpentry, otherwise lying freely in the cavity and only attached at the bases of the fistulse. — Spongiu was not observed, neither in the inner skeleton nor in the dermal skeleton. — Carter has not seen the construction of the skeleton of the inner body; in his material the inner body has probably been destroyed. Both in the dermal layer and in the inner body many foreign particles are imbedded, especially Globigerinae. Spicula : a. Mcgasclera ; these are only of one form, tylotes, but with some single intermediates The Ingolf-Expedition. VI. 3. 2 IO PORIFERA. III. to strongyles. They are more or less curved, but rather slightly; the shaft is thickest at the middle and tapers somewhat towards the ends. The spicules vary very much in size, and at the same time somewhat in shape; the smaller and thinner they are, the more distinct are the end-swellings; these smaller spicules have equal or nearly equal ends; the larger and thicker the spicules are, the smaller are relatively the end-swellings, so that in the largest of the spicules they may be onlv slightly pronounced; in the largest spicules the ends are most often not equal, one has a somewhat roundish swelling the other an elongated swelling tapering slightly outwards; not rarely the swellings quite disappear, and then we get a strongyle with unequal ends, one rounded the other more tapering, nearly truncately pointed. The various sizes must be taken to be fully developed spicules, since fine developmental stages in various lengths are found; the developmental stages have unequal ends, the shaft being a little thicker in one end but a little thinner in the other, and here with a more marked swelling. Quite single very fine developmental stages were found, which had one end quite pointed. The length of the spicules is in all 0*27— o-95mm, with a diameter of 0-005 — o-02imm. The length of the spicules is different in the different parts of the sponge; in the dermal layer the largest are found, while the smaller and smallest are found in the inner body, the separation is how- ever not quite sharp. In the inner body they generally do not exceed o-6omm, and about at the same size also lies the lower limit for the spicules of the dermal layer. In the skeleton of the fistulae large and small spicules are mingled. In the fibres running along the surface of the inner body the spicules belong for the most part to the larger forms of the group with the smaller spicules, and among them some of the largest spicules are found, and with this composition the fibres continue out through the fistulae. Carter mentions and figures two forms of megasclera; to this result he arrives only by taking a pronounced tylote and a form without end-swellings, and in which one end is truncately pointed ; a form such as his figure 39 a may be found, but not frequently, and there is, as said, only one kind of megasclera. b. Microsclera ; there are two forms, chelae arcuatse and sigmata. 1. The chelae arcuatae have an evenly curved shaft, lobe-shaped alae and an elliptical tooth; their length is 0-040— 0-046 mm and the diameter of the shaft is 0-004 mm. 2- The sigmata are of common shape and more or less contorted; they are rather large, but they vary somewhat in size, the length is 0-047 — °'°93 Inm and the thickness 0-0028 — 0-0057 m,n. The microsclera are present through the whole sponge, they are scattered in the inner body and in the dermal layer strewn rather numerously among the megascleres, and they are specially numerous on the inside of the fistula;; the sigmates are everywhere more numerous than the chelae. Embryos. In one of the specimens which was cut through an embryo was found, lying in a cavity in the inner body. It was globular and rather large, 3'nm in diameter. It was lying in the cavity distinctly surrounded by a membrane. It was richly provided with spicules, both megasclera and microsclera. The megasclera were fine tylotes of a greatest length of about o-47mm, many of them were very thin and had still one end pointed. They were scattered in the interior of the embryo, but they were already close-lying at the surface and parallel to this, thus forming a layer with how- ever no boundary inwards. The microsclera were developmental forms of chelae in various stages, they were of somewhat different sizes, but reached a length of up to 0-057 mm, tnus to a greater size than in the fully developed sponge. Sigmates were not seen. PORIFERA. III. u We have a specimen of this species which I at first thought was a distinct form on account of its smaller spicules, but which on closer examination proved to be a very young specimen of appeiidiculatuiii. The specimen is globular, with a single fistula, and very small, about 3mm in diameter, and thus not larger than the examined embryo. It shows quite the same structure as the full-grown specimens; it has a distinct dermal layer with subdermal cavities below, and also distinctly shows the skeletal structure of the inner body. The specimen is interesting in showing, that such small specimens may have considerably smaller spicules than the grown specimens. It is yet no doubt only the very small specimens which show in this respect any difference worth mentioning, and it is certainly the case, that they very soon get spicules of the size normal to the species. The examined specimen has probably just left the mother-sponge. The megacleres do not reach beyond 0-41 mm, the chelse are crc^o'1"", and the sigmates are of the same sizes as in the full grown sponge. It is interesting to notice, that the chelae in this specimen are intermediate in size between the cheke in the embryo and those in the grown sponge. The relatively long and fine megascleres in the embryo seem here to be replaced by shorter but thicker spicules. Locality: Station 78, 6oc 37' Lat. N., 270 52' Long. W., depth 799 fathoms, about 29 more or less damaged specimens; station 90, 640 45' Lat. N., 290 06' Long. W., depth 568 fathoms, two specimens and some loose fistula; ; further at 6i° 15' Lat. N., 90 35' Long. W., depth 478 fathoms, a very small specimen (The fishery investigation steamer "Thor"). The localities are situated on the eastern slope of the Reykjanaes Ridge, in the Denmark Strait and West of the Faroe Islands. Gcogr. ciistr.: Carter had the species from the west coast of Ireland, depths 808 and 109 fathoms. (Porcupine). 2. H. physa O. Schmidt. PL I Figs. 12—13, PI. IV, Fig. 3. 1875. Dcsiuacidon physa O. Schmidt, Jahresber. der Conim. zur wissensch. Uuters. deutsch. Meere in Kiel fur 1872—73, 118, Taf. I. Fig. 8-9. 1887. Cornulum ascidioidcs Fristedt, Vega Exp. wetensk. Jakttag. IV, 495. PI. 25, figs. 1 — 2, pi. 29, fig. 21. 1903. Histodcrma physa, Arueseu. Berg. Mus. Aarbog 1903, 16, Taf. II, Fig. 5, Taf. Ill, Fig. 9. 1903. — — , Thiele, Arch, fur Naturgesch. Jahrg. 1903, 385, Taf. XXI, Fig. 16 a— b. 1909. — — , Lundbeck. Meddel. om Gronland, XXIX, 443. Roundish or more irregular, sometimes somewhat erect, attached with a broad base: provided with one or a couple of conical spouts. Surface smooth. The sponge surrounded by a solid, but not thick, bladdery derma/ lexer. Oscula at the summit of the conical spouts, the pores on the side of these. The dermal skeleton formed of close-lying spicules parallel to the surface. The skeleton of the inner body consisting of fine fibres and bundles of spicules, running irregularly, but at the surface parallel with this; without transverse fibres. Spicula: Megasclera strougyla with intermediates to subtylota, o-jjo—o-8pmm; microsclera of two forms, chela arcuatce crojs — o-oj-2g — cn5j""", acanthoxca o-ij — 0-21"""; microsclcra two forms, chela" arcuatce 0-021 — cro28mm, sigmata o'o^6 — o-o6i""". This species in its exterior shape somewhat recalls Histoderma appendiculatum. but it is generally less regular. Most frequently it consists of a more or less roundish body with a varying number of tube-shaped appendages. These appendages or fistulse may vary much in length and thickness, and there are often, besides the larger, also some short and thin fistula?; these may be branched in different ways, and they may be more or less curved; the appendages also may form swellings, the sponge in this case consisting of more than one roundish swollen part connected by the appendages. Finally there are specimens which have no pronounced swelling, or no swelling at all, the sponge then consisting of a somewhat sinuous, slightly branched tube of somewhat different thickness in different places. In the largest specimen the body has a diameter of fully 20""11, the longest fistula has a length of 42 """ and its thickness is 4mm; then we have specimens in all sizes down to quite small, the smallest one has a body with a diameter of 2-5 mm and a fistula of a length of 14 mm and a thickness of 17 mm. The sponge grows freely without any attachment. The colour (in spirit) is yellowish white. The consistency is somewhat bladder-like, the outer layer is hard and firm, the inner body brittle, the latter is as usually highly contracted, so that it only occupies a small part of the cavity within the dermal rind. The surface is mainly smooth, yet the ends of the tangential spicules of the dermal layer may sometimes be a little projecting. The sponge is outermost sur- rounded by a solid and hard dermal layer, formed of close-lying spicules, the layer has a thickness of about o-2mm. Oscula and pores: A part of the fistula; are distinctly seen to be oscular fistulse, they terminate with a simple opening, or they are in most cases more or less closed and terminate in a conically pointed part which is either quite closed or shows an opening at the summit. Pores I have not observed, but they are certainly placed at the end of some of the fistulse; in my material however the outer part of these is often broken off; at all events pores are not found otherwise on the body. The inner body is in nearly all specimens strongly contracted or quite destroyed, yet in some single specimens it may be seen to have had a surface as in Histoderma appendiculatum, with pores leading into canals; the direction of the water-current therefore is probably the same as in that species. The skeleton. The dermal skeleton; the skeleton of the dermal layer is constructed as in H. appendiculatum; it consists of close-lying tangential spicules in several layers, the spicules are more or less circularly arranged around the bases of the fistulse, and here likewise, especially on the inside of the layer, we find spicules which lie at right angles to the others, these latter spicules PORIFERA. III. 15 being for a great part spined oxea. The skeleton of the fistulse is also here arranged ring-like, but outwards it soon becomes more irregular and scattered; fibres running through the fistuke in longi- tudinal direction are not found here, or they are at all events only very little pronounced and soon dissolved into spicules lying more scattered in the longitudinal direction. The skeleton of the inner body is constructed quite as in //. appendiculatum ; there are fine, parallel fibres running along the surface and without connecting transverse fibres, and they run together at the bases of the fistulae, some of them may continue out in the fistulae; in the interior of the inner body similar fibres are found, but they are scattered without observable order; besides there is found a number of single, scattered spicules, which for a great part are spined oxea. Spongin could not be observed in the skeleton. Spicula: a. Mcgasclera; these are of two forms, tylota and acanthoxea. 1. The tvlota are straight or slightly curved, they have a well developed swelling at either end, the shaft is thickest in the middle. The length varies much, from 0-29— 0-65 mm, with a diameter of the shaft relatively of 0-007 — 0-017 mm. Some developmental stages are found down to quite fine, the thinnest of them are monactinal, the older show one end rounded or slightly swollen, while the other end has a pointed swelling which represents the original apex, and the shaft is thinnest at this end. There is no differ- ence between the tylotes in the dermal layer and those in the inner body, but the developmental stages are found in the interior. 2. The spined oxea or acanthoxea are curious and characteristic spicules; they are straight or quite slightly curved, and relatively short and thick, the points are middle-long and sharp; the spicule is coarsely spined in the whole length, only the points are smooth to a greater or smaller extent. The length varies from 0-17— 021 mm and the diameter from 0-008— 0-014. Some single developmental stages were seen, the thinnest of them slightly spined, these had a thickness of 0-004 mm. The tylotes form the dermal layer and the fibres in the inner body are also found scattered singly in the interior; the spined oxea are seen scattered singly in the dermal layer, but are for the rest present, as said, on the inner side of the layer, lying at right angles to the other spicules, further they are found scattered in the inner body. b. Microsclera; these are of two forms, chelae arcuatse and sigmata. 1. The chelae are somewhat small, they have a slightly curved shaft, the alse are incised below and drawn out in a point, the tooth is narrow. The length is 0-02 1 — 0-028 mm, and the thickness of the shaft about o-oo2mm. Chelae of somewhat deformed shape were not infrequent. 2. The sigmata are rather fine, they are contorted generally about a quarter of a turn; the length is 0-056— 0061 mm and the thickness 0-002— 0-0028 mm. The microscleres occur on the inside of the dermal layer and in the inner body, but they are on the whole not numerous. "Cellules spheruleuses". In this species the so-called cellules spheruleuses occur, often in enormous numbers; they occur especially on the inside of the dermal layer and the fistuke and in the inner body, chiefly at the surface of the latter. They are roundish or more elongate and filled with relatively large, refracting granules; their size is generally o-on— 0-017 ram. Sometimes they are some- what confluent to larger heaps of granules. Locality: The species has only been taken on station 78, 6o° 37' Lat. N., 270 52' Long. W., depth 799 fathoms, on the eastern slope of the Reykjanees Ridge; a somewhat large number of specimens. l6 PORIFRRA. III. 2. H. coriacea n. sp. PL II, Figs. 5-6, PI. IV, Fig. 5. Elongate, somewhat fusiform, sometimes cylindrical or more irregular and somewhat branched; provided with generally short, papilla-shaped fistula in greater or smaller number. Growing freely, with- out attachment. Surface somewhat rough, but without projecting spicules. The sponge is surrounded by a very solid dermal layer. Oscula and pores each at the summit of their own papilla*. The dermal skeleton formed of close-lying, tangential spicules. The skeleton of the inner body consisting of scattered spicules. Sficula: megasclera of two forms, slrongyla with spinulous ends 0-24 — ro2""", acantiiostrongyla o'T2 — o-2j8mm. No microsclera. This species has an exterior which certainly resembles that of the preceding species but how- ever is somewhat different, and it is larger and more robnst. It consists of a body with fistulse, but the body is never globular but elongated, generally somewhat fusiform, thickest in the middle and somewhat tapering towards the ends; it is otherwise generally more or less irregular. Sometimes it is not fusiform, and the sponge is then nearly cylindrical; sometimes it is somewhat branched. The fistulas are generally rather short, often nearly papilliform and they are for the rest very irregular both in shape and arrangement, and they may also be branched. When they are somewhat larger they appear as branches, so that the sponge then assumes the branched shape. Most of my specimens are somewhat damaged, but to judge from not damaged specimens the species is not attached, but grows freely, which is also by far the most probable. The largest specimen, which is not quite entire, has a length of about ioomm and a greatest thickness of 17 mm; the other specimens are somewhat smaller, down to about 50mm in length. The colour (in spirit) is in most specimens whitish grey or dirty greyish violet, the inner body is darker than the dermal layer and is obscurely reddish violet; some of the smallest specimens are nearly cpiite white, but also in these the inner body is somewhat darker. Whether the colour is original or due to the influence of alcohol has not been observed. The consistency is, on account of the very thick dermal rind, very firm, the inner body is also in its present condition rather firm, but brittle; it is strongly contracted and lies generally up to one side of the dermal layer. The surface cannot be termed smooth as the close-lying spicules cause it to be rough both to the sight and to the touch, but it has no projecting spicules. The sponge is outermost surrounded by a very solid and hard dermal layer, provided with close-lying spicules; this layer is very thick, from 0-4— cr8mra. Pores and oscula: Some of the fistulae or papillse are oscular papillae; they are distinguished by their conical shape, pointed towards the end, with an oscular opening at the summit. The papilliform ends of the sponge-body itself are oscular papillae. From the oscular opening a canal, which is surrounded by a film-like membrane, leads down into the body. The other papillae, which bear no oscula, are pore-papillae. These fistulae or papillae are of a different shape from the oscular papillae, they have rounded ends which are as a rule a little swollen; they are present in greater numbers than the oscular papillae. The pores are only present in the outermost, rounded end-part of the papillae. In the middle, through the interior tissue of the papilla, runs a canal which in the outer end-part of the papilla is divided into branches; these branches go to the surface and are the incurrent canals into which the pores lead; these latter are lying in an irregular reticulation POR1FERA. III. 17 and they have a diameter of 0-036— o- 10 mm. The circulation of the water-current is then the same, as was mentioned under II appendiculatum; there is also here a space below the dermal rind, and in a section of the inner body parallel with the surface the small, round incurrent openings to the canals are, under the microscope, seen lying very closely. The skeleton. The dermal skeleton; the skeleton of the dermal layer is formed of close-lying, tangential spicules, which lie in several layers and form a solid and protective rind. The greatest part of the spicules lie parallel to each other in a direction which goes more or less distinctly circularly round the sponge, thus the spicules lie at right angles to the longitudinal direction of the body of the sponge; at the same time they are, in the environs of the fistulae, arranged ring-like arouud the bases of these. When the surface is undamaged, there is outermost a layer of more loose- lying spicules which lie crossing each other in all directions; between the regularly arranged spicules of the layer there are spicules placed at right angles to the others. A section through the layer parallel to the ring-like arranged spicules will thus show entire spicules King parallel to each other on the inside, and cut, irregularly lying spicules on the outside. The spined strougyla occur especially at the outer side. The skeleton in the fistulae is ring-like arranged at the base, but outwards it passes soon into an irregular skeleton with spicules intercrossing in all directions; in the oscular fistulae the spicules are in the conical summit arranged parallel to the longitudinal direction and with one end towards the oscular opening; in the pore-fistula; there is at the end an irregular reticulation, in the meshes of which the pores lie. The skeleton of the inner body is difficult to get a clear idea of on account of the brittleness and contracted condition of the tissue, and also on account of its very dark colour. It is however not regular as in the preceding species, but seems only to consist of scattered spicules; at the surface they are present in greatest numbers while they are much scattered in the interior, and they are on the whole not numerous. Spongin is not present in the skeleton. Spicula : a. Megasclcra ; these are of two forms, smooth strongyla and acanthostrongyla. 1. The smooth strongyla are straight, more rarely quite slightly curved, they are thickest in the middle and taper slightly towards the rounded ends, which latter sometimes may be quite slightly swollen. The ends are very finely spinulous on the rounded part; the spinulation may be very little apparent but is generally rather distinct, it is most obvious on the smaller spicules. The length varies much, from o-24mm and up to ro2mm, and the thickness is 0-008— 0-021 mm. In the dermal layer strongyla of all sizes are found, the larger are present in greatest numbers, in the inner body on the contrary only the smaller forms are found, up to a length of 0-47 n'm, but at the surface of the inner body they are somewhat larger up to o7in,n'. 2. The acanthostrongyla or spined strongyla are relatively short and thick; they are generally sligtly curved, coarsely spined strongyla, sometimes each end terminates in a point, but as this is not, or only very slightly, larger than the other spines, it must be taken as such and the spicule must be termed a strongyle. The length is about 0-12 — o-238mm, the shortest forms occur most rarely, the thickness is o-on— o-or.7mm. The acanthostrongyla occur both in the dermal layer and the inner body scattered between the other spicules; in the dermal layer they are especially present towards the outer side. Microsclcra are not present. Locality: This is the same as for the preceding species, viz. station 78, 6oc 37' Lat. X., 27° 52' Long. W., depth 799 fathoms. The Ingolf-Expedition. VI. 3. 3 PORIFERA. III. This species seems to be very like Phloeodictyon birotuliferum Cart. (Ann. Mag. Nat. Hist. 5, XVIII, 447), to judge from Carter's figure and description. This resemblance however is probably only an analogy, without consequence in regard to affinity of the species (see below under the remarks about the species of the genera in question). The two Histodermella species established here, Ingolfi and coriacea, are certainly rather nearly related to each other; the outer shape, the dermal rind and the arrangement of the canal system are in agreement; the differences lie mainly in the construction of the skeleton of the inner body and the shape of the spined megasclera as also in the absence of microsclera in one species. Inflatella O. Schmidt. (Joyeuxia Topsent.) The shape roundish or the sponge more or less club-shaped, sometimes pedunculated. The con- sistency bladder-like. The body provided with more or less numerous papilla. An outer, solid dermal layer present, with a skeleton of close-lying spicules; the skeleton in the inner body -weak, consisting of thin fibres, not forming any reticulation. Spongin not present. Spicula ; Megasclera of one form, diac final, strongy/a ; microsclera not present. 1. I. pellicula O. Schmidt. PI. II, Figs. 7—9, PI. IV, Fig. 6. 1875. Inflatella pellicula O. Schmidt, Jahresber. der Comm. zur wissensch. Unters. der deutsch. Meer. in Kiel fur 1872—73, 117, Taf. I, Fig. 5. 1885. Reniera inflata Armauer Hansen, The Norwegian North-Atlant. Exp. XIII, Spongiadae, 7, PI. I, fig. 4. 1903. Inflatella pellicula. Thiele, Arch, fiir Naturgesch., 1903, 385, Taf. XXI, Fig. 17. 1904. Joyeuxia viridis Topsent, Resultats des camp, scient. du Prince de Monaco, Fasc. XXV, 205, PI. Ill, fig. 12. Club- or pear-shaped, pedunculated, with some fen' conical papilla" above. The surface smooth, flic sponge surrounded by a solid dermal layer. Oscula and pores at the summit of the papilla-. The dermal skeleton formed of close-lying, tangential spicules; the inner skeleton consisting of bundles or loose fibres. Spicula: Megasclera strongyla 0-42 — 0-64""". The outer shape of this species is somewhat well known from the descriptions cited. It is elongate, pear-shaped and is attached below by a shorter or longer peduncle to a substratum. The peduncle may with regard to the manner of fixation be somewhat various; either it is only fixed by means of a little dilatation, or it emits stolons which may shoot out at various heights, and each of which has its own attachment. This is already mentioned by Schmidt 1. c. Of the figures cited above that given by Schmidt shows stolons, while the others show a single peduncle; the figure by Topsent, however, shows a small projection above on the peduncle, evidently a beginning stolon, as is also mentioned by the author. Above, the peduncle passes into the pear-shaped body which bears one to four slender, conical papillae above. The specimen described by Topsent shows an osculum without papilla. Of the specimens in my material the largest is 19""", the smallest iomm high; PORIFERA III. J9 the specimens previously described are of similar sizes. The papillae vary in length from 1*5 to 4""". The colour (in spirit) is in one specimen green, but otherwise whitish, presumably on account of de- colouration. The consistency is bladdery, the dermal layer being firm and solid, while the inner body is soft and strongly contracted. The surface is smooth. The dermal layer is a rather thin, firm mem- brane, provided with close-lying spicules. Pores and oscula . The pores are certainly found at the summit of certain papillae, as in one of the papillae 1 found a very distinct, sieve-like pore-membrane with close-lying, circular pores, but as my material is somewhat damaged and only shows few papillae, I can say nothing further, but there are no pores found otherwise on the surface. Some others of the papillae are oscular papillae with a simple opening at the summit. That the papillae are partly oscular, partly pore-papillae is also confirmed by what is found in the following species /. viridis. The skeleton. The skeleton of the dermal layer consists of close-lying, tangential spicules, inter- crossing each other in all directions; they lie rather closely, but not more closely however than that the membrane ma)- be seen everywhere between them. In the peduncle they lie quite closely and here they are all arranged parallel to the longitudinal direction; the layer is also here considerably thicker, and the spicules lie in several layers; the peduncle, however, is not compact, but the inner cavity continues down through it. In the wall of the papillae the spicules likewise lie quite close to each other and all parallel to the longitudinal direction with one end towards the opening of the pa- pilla. The skeleton of the inner body I have only been able to examine somewhat incompletely, as the specimens in my material for the most part want the inner body; it is however not at all devoid of a skeleton; there are bundles and loose fibres present which seem mainly to have a course along the surface, but whether there is otherwise any definite arrangement I have not been able to see. Spongin is not present in the skeleton. Spicula: a. Megasclera; these are of one form, strongyla; they are slightly, generally somewhat irregularly curved; they are thickest in the middle and taper a little towards the ends; these latter are sometimes, either one or both, slightly swollen; there is often a little difference between the ends, one being slightly thinner than the other, but most frequently such a difference is not observable. The length is 0-42 — 0-64™'", most frequently about intermediate between these sizes, the thickness is o-oio— o-oi28mm. Fine developmental stages were found singly, they are monactinal, and they are especially found in the inner body. Microsclera not present. As I have examined the type-specimen of the Reniera inflata Arm. Hans, the identification of this with the present species is certain. — While the Joyeuxia viridis Tops. (1. c. 1904) must be the present species, the two specimens which this author described in 1892 for the first time (I.e. Fasc. II, 94.), and on which he founded the genus Joyeuxia and the species viridis, are on the contrary probably a distinct species and identical with the species described below. Locality: The Ingolf-Expedition has taken three specimens of this species on the following localities: station 32, 66° 35' Lat. N, 560 38' Long. W, depth 318 fathoms; station 81, 6i= 44' Lat. N., 27° 00' Long. W., depth 485 fathoms, and station 97, 650 28' Lat. N., 270 39' Long. W., depth 450 fathoms. The localities lie in the Davis and the Denmark Straits. Gcogr. distr. The species has earlier been taken South-west of Bukenfjord, Norway, depth 106 fathoms (Schmidt 1. c.) and at 380 31' Lat. N., 260 50' Long. W., depth 449 fathoms. The species is thus 3* 2o PORIFERA. III. distributed in the Atlantic Ocean together with the Denmark and Davis Straits between 66° 35' and 38°3i' Lat. N., and with a bathymetrical range from 106 to 485 fathoms. For the specimens from the Norwegian North-Atlantic Exp. no particular locality is known. 2. I. viridis Tops. PI. II, Figs, n -12, PI. IV, Fig. 7. 1S92. Joyeuxia viridis Topsent, Resultats des camp, scient. du Prince de Monaco, Fasc. II, 94, PL II, fig. 8, PL X, fig. 19. Erect, somewhat club-shaped, or of a lower and somewhat seiniglobular shape; there are more or less numerous papilla in the upper part. Surface smooth. Outermost there is a solid dermal layer. Oscula and pores each at the summit of their own papillic. The dermal skeleton formed of close-lying tangential spicules in several layers; the inner skeleton consisting of bundles and thin fibres running parallel with the surface, without transverse fibres. Spicula; Megasclera strongyla cr66 — no""", This species differs from the preceding one externally in being considerably larger and in having no peduncle. Of the specimens in my material only three are tolerably entire; of these the two are erect and somewhat club-shaped, being a little narrowed below, the third is lower and relatively broader. Above, the sponge has more or less numerous conical papillae; below, it has been attached, and it would seem as if it had grown on the bottom itself, the base of attachment being beset with gravel and other .small particles. The largest of the entire specimens has a height of 30"'™, and a breadth of about i8ram, and at the base a breadth of fully iomm; another specimen of a similar shape is somewhat smaller; the lower and broader specimen has a height of about 20 mm with a breadth of about 15 mm. The colour is (in spirit) light brownish yellow or olive; the colour of the inner body is deeper than that of the dermal layer. The consistency is bladdery, the outer layer hard and firm, the inner body brittle and soft. The surface is smooth. The dermal layer is provided with tangential spicules in several layers, and it is somewhat thicker than in / pellicula and reaches a thickness of about 0-5 mm, in places even more. Oscula and pores; the papillae mentioned are partly oscular and partly pore-papillae. The oscular papillae are conical, of a height of 3""", but they may contract themselves and are then quite low. When they are open the osculum is a simple opening at the summit. In the wall of the papillae the spicules are close-lying; they do not lie, however, in the longitudinal direction but in two directions crossing each other almost rectangularly and both obliquely to the longitudinal axis of the papilla; when the papilla is quite extended the two sets of spicules are arranged in rather distinct, but close-lying bands, but when the papilla is contracted and the osculum closed the spicules form a compact mass and when the papilla is then examined from the end the ends of the close-lying spicules are seen. The pore-papillae are of another construction and easily distinguishable from the oscular pajsillae; they are larger, especially broader, and they are not conical but cylindrical; they are generally placed on the sides of the upper part of the sponge, and they are not directed straight outwards but somewhat upwards so that their opening points upwards, they are at the same time somewhat adpressed in towards the sponge and hence elliptical in circum- ference; they have a breadth of 6— ioram; on account of the manner in which they are attached, their PORIFERA. III. 21 anterior wall is higher than the posterior, which is towards the sponge, e. g. 6 and 3""" respectively. The elliptical opening is covered by a somewhat immersed pore-membrane, with very close-lying pores, so that the membrane is sieve-like; the pores have an average diameter of 017"". The walls of the papillae are provided with spicules which do not lie in the longitudinal direction, as is also the case in the oscular papillae; they are here distinctly arranged in two sets of bands crossing each other more or less rectangularly, and placed more or less obliquely to the longitudinal axis of the papilla; this oblique direction shows for the rest a definite arrangement; while the bands on the hinder side of the papilla form an angle of 450 to the longitudinal axis, those on the anterior side are more erect and most so on the middle of the anterior side; the bands form by their arrangement a close reticulation with square or subqua- draugular meshes. In the pore-membrane no spicules are found. The oscula are present in greatest number e. g. up to seven, of pore-papilla; on the contrary only one or two are found.1) The surface of the inner body shows under the microscope an appearance almost as in Histoderma appendiculatum : through the surface shine the openings of close-standing incurrent canals; the course of the water- current will thus be through the pore-sieves into the extended subdermal spaces, from here through the fine pores in the surface of the inner body into the canal system, and then out through the oscula. The skeleton. The skeleton of the dermal layer consists of tangential spicules in several layers; the spicules are rather close-lying, but yet the tissue may everywhere be seen between them; they intercross each other in all directions without any observable order, only a slight tendency towards collecting into bundles is seen, with only few spicules in the bundles. The skeleton of the oscular and pore-papilla; is described above. The skeleton of the inner body. As in I. pellicula a close examination shows that the inner body also in the present species is provided with a skeleton; in the interior this skeleton consists only of quite single scattered bundles, but on the other hand it forms distinct fibres at the surface, running parallel with this, and it is thus in the main constructed as in the species of Histoderma. As far as I could observe no spongin is found in the skeleton. Spicula: a. Mcgasclcra are of one form, strongyla, the)" are more or less, generally somewhat irregularly curved, more rarely straight; sometimes the curve is somewhat sharp; they are thickest in the middle and taper somewhat towards the ends but most frequently only to a slight degree. The length varies a deal, from 066— nomm, they are rather slender, the thickness is in the middle cron — 0*014 mm. Fine developmental stages, which are monactinal, are found in the inner body. Embryos. In a couple of specimens embryos were found; they were lying in the inner body close to the dermal layer; they are globular, of a diameter of about ovj.8 n,m; the examined embryos showed no spicules. Whether this species is really identical with Topsent's viridis it is difficult to decide, but as the only difference is, that the spicules in Topsent's species are somewhat smaller, 076""", there is good reason to take them as identical. When Topsent declares, that the inner body is quite 'J Since this was written the work of Kirkpatrick iNat. Antarct. Exp. Nat. Hist. IV, 1908) has appeared; here the author describes a very interesting species I. Belli (Joyeuxia) (41, PI. XVI, figs. 1 - 5 ai ; this beautiful Inflatella has on the surface numerous papillae, easily seen to be oscular and pore-papilla;; the pore-papilla.- are about I™ long, trumpet-shaped, with a pore-sieve over the wide opening; the oscular papillae are simple and smaller, about 4""' long. In this species the facts with regard to oscula and pores are thus principally the same as described above, but both kinds of papillae are much more developed. 22 PORIFERA. III. without spicules, these have surely only been overlooked. Topsent's specimen had lost the upper part, and oscula and pores therefore were unknown to him, and consequently it is incorrect, when he says, that pores pierce the dermal layer singly. Locality: Station 92, 64° 44' Lat. N., 320 52' Long. W., depth 976 fathoms; about five more or less damaged specimens. Gcogr. distr. The species has been taken 250 right south of the Iugolf locality between 380 and 390 Lat. N., at the Azores in depths of 241 and 391 fathoms (Topseut 1. a). Remarks. Topsent says (I.e. 1904, 207) that still another species'belongs to Inflatella (=Joyeuxia), viz. ascidioides Fristedt; this species, however, is identical with Histoderma physa, as mentioned above under this species. When Topsent says in his generic diagnosis, that chelae may occur in the genus, this is therefore erroneous. Inflatella sp. Vosmer (1885. Bijdr, tot. de Dierk. i2u Afl. 3^' Gedeelt. 21, PI. I, fig. 8, PI. V, figs. 17—19) is a Vosmaeria. Cornulum Cart. The shape somewhat various, the sponges being erect and obconical or more roundish or semi- globular wit// a broad base. The consistency somewhat bladder-like. Wit// or without fistuloe. Outermost a solid dermal layer with close-lying spicules. The skeleton somewhat solid, consisting of rather thick fibres, dendritical or reticulated. Spongin present. Spicula: Megasclera diactinal, oxea or strougyla, the latter sometimes with the ends finely spinulous: the megasclera are either of one form and equal through the whole sponge, or of two forms, oxea in the skeleton and strougyla in the dermal layer; microsclera : the characteristic microsclera are isochelcr palmatce either solely, or (textile) together with toxa. 1. C. textile Cart. PI. II Figs. 13—14, PI. V, Fig. 1. 1876. Cornulum textile Carter, Ann. Mag. Nat. Hist. 4, XVIII, 309, PI. XII, fig. 9, PI. XV, figs. 28 a— b. 1887. — , Fristedt, Vega Exp. vetensk. Jakttag. IV, 446. 1909. — — , Lundbeck, Meddel. 0111 Gronland, XXIX, 443. Erect, obconical, with a flat upper surface. Outermost a thin but solid dermal layer. Surface smooth. Oscula lying to one side in the upper, flat plane, fores occupying the rest of the plane. The dermal skeleton formed of rather close-lying spicules in one layer. The inner skeleton strongly developed, regularly dendritical, consisting 0/ fibres which go upwards from the base and bend out to the surface, they arc connected by transverse fibres. Spicula: Megasclera one form, strougyla with finely spinulous ends, o-jj—u-jjd""": microsclera of two forms, cliche palmatce 0-014 — iro //""". toxa, long and fine, o-2i — o-jo""". This curious and interesting species has on the whole a shape as described by Carter 1. c. It is erect and has been attached with its lower, quite slightly dilated or swollen base to some object on the bottom; all the specimens in my material are, however, torn off, but the flat attachment is distinct. Carter also says: "attached to hard objects". From the base it rises upwards with a stalk- PORIFER.V III. 23 shaped part, but it gradually increases evenly in thickness and reaches its greatest diameter at the upper end. To judge from a couple of specimens which have the upper end tolerably undamaged, the sponge is here suddenly and slightly obliquely cut, with a plane upper surface, which perhaps has had an oscular tube; it is thus of a slender obconical shape, and is generally quite slightly curved, so that it may very well be compared with a horn, as Carter says; further the sponge has some more or less distinct, ring-like contractions. The size is about the same in all the specimens in my material, the length 30— 40 mm, the thickness above 6— iomm. Carter's specimen had a similar size. The con- sistency is bladdery but, on account of the firmness of the outer layer, somewhat solid. The colour (in spirit) is yellowish white. The surface is smooth. The dermal membrane is a thin, but firm and solid membrane, provided with close-lying spicules arranged in one layer. Oscula and pores: Carter supposed that oscula and pores were placed in the upper end of the sponge, but his specimens were damaged here; my specimens also are more or less damaged in the upper end, yet a couple are so much undamaged, that they give some information with regard to the place and structure of the oscula and pores. The upper surface of the sponge is, as said, somewhat obliquely cut and is thus in the main plane; on this lie an osculum and the pores. The osculum is a nearly circular opening with a slightly projecting edge, it has a diameter of 1-5 mm; it is in both the examined specimens placed close to the margin of the upper surface and a wide canal leads from it down towards the base of the sponge. In the other part of the upper surface lie the pores, they are circular or oval and so close- lying that a sieve is formed; the incurrent openings to a number of canals are seen shining through the pore-membrane; the pores are of a size of 0-023 — o-i2mm. The skeleton: The dermal skeleton. The outer membrane is provided with spicules lying close to each other in one layer, but they are not closer than that the membrane may be seen everywhere between them; the spicules are parallel with the surface and mainly arranged in the longitudinal direction of the sponge; on the inside of the membrane some spicules are found which are arranged at right angles to the others and thus lying transversely, they lie singly or a few together. The membrane thus furnished is a little projecting above in the circumference of the sponge, and here the spicules also project; the pore-membrane, which covers the upper surface of the sponge, is pro- vided with a skeletal reticulation, forming the meshes in which the pores lie; this reticulation is for a great part unispicular and irregular. In the part of the membrane surrounding the oscular aperture, there are some short fibres, directed towards the aperture. The main skeleton is of a regular, dendritical construction; from the base fibres go upwards through the sponge; in the centre they are most powerful, and from here fibres steadily bend outwards which, running obliquely upwards, go to the surface; these fibres have a somewhat regular course and are parallel with each other, and they are connected bv transverse fibres, which, however, are placed more irregularly; the fibres are strong and consist of many spicules; they have an average thickness of o'i2mm, those in the middle being still thicker; the transverse fibres are thinner. The distance between the longitudinal fibres is about o-5mm. Above, the fibres spread themselves out and support the membrane of the upper surface, and the spicules are here a little projecting. As will be seen the skeletal reticulation thus formed is rather regular, and the skeleton is intermediate between a dendritical and a reticulate skeleton. In the skeleton a distinct amount of spongin is found, which in most places may be seen to coat the fibres with a 24 PORIFERA. III. layer; spongin is also present in the dermal membrane, and on examination the membrane gives the impression of being quite or partly a spongin-lamella; the spongin of the skeletal fibres continues directly over into the membrane. It is this consistency of the membrane about which Carter uses the expression "a horny sarcodic membrane". In the membrane there are found fine thickenings or slightly elevated lists running circularly round the sponge, they seem to be thickenings of the spongin, and are possibly phenomena of growth. Spicula: a. Megasclera are somewhat curved strongyla, they are thickest in the middle and taper towards the ends, more towards one end than towards the other, and they are thus unequal-ended. The ends are quite slightly spinulous outermost on the rounded part, sometimes they may be smooth. The length is 0-32 — 0*536 mm and the thickness is 0-017— o-022mm. Some finer to quite fine develop- mental stages were seen, the finest are monactinal and thus show that these unequally-ended strongyles originate from styles, b. Microsclera ; these are of two forms, isochelse palmatse and toxae. 1. The chelse palmatse are very small and of the typical shape, the tooth is of the same length as the alee and of the same breadth as these together; the alse seem to be only very slightly refolded laterally so far as I could see under a high magnifying power (x 1400). The length is 0-014 — 0-017 ran' and the breadth about o-oo28mm. 2. The toxa are long and fine, the curvature is most frequently very slight; sometimes they are only curved in the middle, but most frequently also the end parts are slightly recurved; sometimes they may be somewhat irregular, so that their shape as toxa is not distinct; they are of the same thickness in the whole length, only the ends are finely pointed. The length is o-2i — o-30mm and the thickness about o-ooi6mm. Carter mentions and figures as "subskeleton spicules" some fine spicules, which he terms "acuate", but his figure shows two, of which one is a style, the other pointed at both ends; it is presumably a confusion of developmental stages of the strongyles and toxa which forms his "subskeleton spicules". I have not seen toxa quite so strongly curved as shown by Carter's figure, but no doubt they may vary a good deal in curvature. The microsclera occur everywhere in the soft tissue of the sponge, the chelse are present in very great numbers. Embryos. In one of the specimens an embryo was found; it was situated about in the middle of the sponge and had a size of about o-6mm. It contained numerous megascleres, but there seemed to be no microscleres present. The megascleres are similar to those in the grown sponge, only con- siderably smaller, of a length of about o-20"'m. Locality: Station 4, 640 07' Lat. N., n° 12' Long. W., depth 237 fathoms; station 143, 620 58'Lat. N., 70 09' Long. W., depth 388 fathoms, (bottom temperature -*-o°4C); further it has been taken at 620 40' Lat. N., i° 56' Long. W., depth 365 fathoms (bottom temperature -=- o° 3 C), 620 29' Lat. N., 40 12' Long. W., depth 283 fathoms (Ad. Jensen, the cruise of vlM. Sars" 1902); finally it has been taken at East-Green- land, 740 17' Lat. N., 1 50 20' Long. W., depth 127 fathoms (The East-Greenland Exp. 1891—92). Five specimens or fragments in all. Geogr. distr. The species was earlier taken on the "Porcupine" Expedition, 6i° 10' Lat. N., 2° 21' Long. W., depth 345 fathoms (bottom temperature -*- i° 1 C) (Carter 1. a), and in the Baffin Bay, 720 32' Lat. N., 560 05' Long. W., depth 116 fathoms. The species is accordingly distributed between 1° 56' and 560 05' Long. W., and between 61° 10' and 740 17' Lat. N., in the Baffin Bay, at East-Greenland and around the Faroe Islands. The depths are from 116—388 fathoms. The species presumably belongs PORIFERA. III. 25 mainly to the cold area, as the localities, as soon as they are deeper than 300 fathoms, show a negative temperature, but it may also go higher up and here occur in water with a positive temperature. Remarks about the species of the genera Histoderma, Histodermella, Inflatella and Cornnlum: Of species which belong here, or have been supposed to belong here, there are at present described the following: 1874. Histoderma appciidiatlahnii Cart, (cited above). . Tylota to strongyla — chelae arcuatae — sigmata. 1875. Desmacidoii physa O.Schmidt (cited above) Strongyla cheke arcuatae -- trichodragmata. 1875. Inflatella pellicula O.Schmidt (cited above).... Strongyla. 1876. HalicJiondria phlyctenodes Cart (Ann. Mag. Nat. Hist.4,XVIII,3i4, Pl.XIII,fig.i7, Pl.XV,fig-35) Tornota -- cheke arcuatae -- sigmata. 1876. Connilum textile Cart, (cited above) Strongyla with spinnlons ends — chelae pal- matae — toxa. 1883. Phloeodictyon singaporeiise Cart. (Ann. Mag. Nat. Hist. 5, XII, 326, PI. XIII, fig. 17 a— b) Oxea -- short strongyla -- chelae palmatae. 1885. Sideroderma navicelligerum Ridley and Dendy, (Challeng. Rep. XX, Monaxonida, 115, PI. VIII, fig. 9, PI. IX, figs. 5, 8—9) Tylota — small peculiar cheke — sigmata of two sizes — trichodragmata. 1886. Histioderma verrucosum Cart. (Ann. Mag. Nat. Hist. 5, XVIII, 452) Tylostrongyla — chelae arcuatae — sigmata. 1886. Histioderma polymasteides Cart. (Ann. Mag. Nat. Hist. 5, XVIII, 453) Tylota to tylotornota — chelae arcuatae? 1886. Pseudohalic/iondria clavilobata Cart. (Ann. Mag. Nat. Hist. 5, XVIII, 454) Tylotornota — chelae arcnatae, enrious, spined. 1887. Cornnlum asci&ioides Frstdt. (cited above) = Histoderma physa. 1887. Connilum euteromorphoides Frstdt. (Vega Exp. vetensk. Jakttag. 447, PI. 25, figs. 3—6, PL 29, fig. 22) se below. 1888. Sideroderma Zittrli Lendenf. (The Austral. Mns. Descrip. Catal. of Sponges, 211) Styli — oxea -- chelae -- rhaphides. 1892. foycuxia viridis Tops, (cited above) Strongyla. 1903. Histoderma natalense Kirkpatrick, (Marine Invertebr. in South Africa, III, 250, PI. V, fig. 17, PI. VI, figs. 18 a— e) Tylota — acanthoxea -- chelae arcuatae - - sig- mata — trichodragmata — curious spined bodies (transformed chelae? or forcipes?). 1904. Joyeuxia tubulosa Tops. (Resultats des camp. sc. du Prince de Monaco, Fasc, XXV, 206, PI. V, fig. 5, PI. XIV, fig. 16) Strongyla. The fagolf-Expedition. VI. 3. •» 26 P0R1FERA. III. 1905. Hisloderma vesciculatum Dendy (Rep. of the Pearl Oyster Fisheries of the Gulf of Manaar, Part III, 166, PI. XI, figs. 8—9) Oxea - - strongyla — ehelse pahnatse. 1908. Joyeuxia Belli Kirkpatrick, (Nat. Antarct. Exp. Nat. Hist. IV, 41, PL XVI, figs. 1—5 a) Strongyla. Histodermella Ingolfi mihi Tylota — aeanthoxea — ehelse arcuatse — sigmata. Histodermella coriacea mihi Strongyla with spinulous ends — acanthostrongyla. Of these species Cormiluni ascidioides Frstdt. is shown above to be identical with Histoderma pliysa O. Schmidt. I have also examined a piece of the type-specimen of Cornulum enteromorphoides Frstdt., and this species proved to be identical with — Myxilla fimbriate Bow., which for the rest may already very well be seen from the description. The specimen, which Fristedt had to examine, was of an elongated shape, and this in connection with the rather strong dermal membrane of this species has led him to refer this typical Myxilla species to Cornulum. Hereafter these two species of Cornulum must be dropped. — Sideroderma Zitfeli Lendenfeld scarcely belongs to the group of sponges here in question. The remaining species will have to be distributed in the four genera treated above, Histoderma, Histodermella, Inflatella and Cornulum. After Carter had established the genus Cornulum with the tvpical and sole species textile, this genus has hitherto only contained the same species, the two erroneous species of Fristedt excepted. With a generic diagnosis as given above, in which the distinguishing characters are first the palmate ehelse, and next the dendritical or reticulate skeleton, formed of strong fibres, two of the above enumerated species, viz. singaporense1-') and vesciculatum must belong to this genus, and the genus seems very natural. Histodermella, which I have founded mainly on characters in the spiculation and for which the typical species is Ingolfi, also includes, besides the two species described here, the Histoderma natalense established by Kirkpatrick in 1903. The above enumerated species will, according to the facts mentioned, have to be distributed in the following way: Histoderma: Histodermella: Inflatella: Cornulum: appendiculatum Cart. natalensis Kirkpatr. pellicula O. Schmidt textile Cart. pliysa O. Schmidt Ingolfi mihi viridis Tops. singaporense Cart. phlyctenodes Cart, (vide coriacea mihi tubulosa Tops. vesciculatum Dendy. remark on page 27) Belli Kirkpatr. navicclligerum Dendy verrucosum Cart. polymasteides Cart. clavilobatum Cart, (belongs perhaps not here but may be an Esperiopsis) Top sent has (I.e. 1904, 198) established a new genus P// lye ta en opora with one species, bistorquis. M Dendy (1905, 1. c.) has shown, by examination of Carter's type specimen, that the species has chelae. PORIFERA. III. which, according to the author, should be placed near to Histoderma; I cannot express myself more particularly about this species, but its relationship with the forms here in question seems to me some- what doubtful. The four genera mentioned are distiugushed among the Myxilleae by the megascleres being the same in the dermal skeleton and in the skeleton of the inner body; this at all events holds quite- good with regard to Histoderma, Histodermella and Inflatella; among the species of Cornulum it holds also good for textile ; in singaporense and vesciculattim there are, to be sure, two forms of megascleres, but they are both diactinal, and they seem not to be sharply divided with regard to their occurrence in the sponge-body. The four genera are certainly nearly related to each other, and as their starting point I think we may take Histoderma as most probable, which shows the least deviating structures; as the genus nearest related to this I take In/latella, which, especially in the skeletal structure, presents the greatest accordance, and on the whole mainly differs only in the want of microscleres, a difference which, when the other structures agree, is of very slight consequence, indeed even the right of Inflatella as a separate genus is perhaps doubtful, but at present I think, there is some reason to keep it. Also Histodermella must be nearly related to Histoderma, one species, Ingolfi, shows both in its exterior and in the skeletal structure great agreement; the curious, spined spi- cules which are present in this genus, are somewhat surprising, but I think they must probably be taken to have their origin from original special skeleton spicules. Cornulum stands a little more apart, distinguished by its palmate chelae. — I thus take these four genera to be nearly related and to represent a- type of Myxilleae in which the original skeleton spicules have disappeared. As said, Histoderma might be thought to form the starting point; the genus outside the group, nearest related to Histoderma, is perhaps Hymedesmia (= Leptosia Tops.); in several species of this genus we find a strong dermal skeleton formed of diactinal spicules, and at the same time the inner skeleton, consisting of the basal acanthostyles, may be very little developed; the acanthostyles may be present in so small numbers, that great care is necessary to avoid mistakes, just in Hymedesmia-species of this latter structure we find at the same time a strongly developed dermal skeleton which also has well developed fibres going from the dermal membrane inwards, and here consisting of the same diactinal spicules which form the dermal skeleton itself. Finally such species may have long, tubular papillae (e. g. Hymedesmia filifera O. Schmidt, and several other species). — It is perhaps a question whether Histoderma phlycte- nodes Cart will not prove to be a Hymedesmia. — When now such species get quite roundish and grow without attachment, as e. g. H appendiculatum , the elimination of the acanthostyles is easily understood, and the transition to the freely growing species is formed by such attached species as for instance Histoderma physa. The genus Melonanchora seems to me to form a beautiful and interesting instance of the opinions here advanced; one species of this genus has the spiculation and skeletal structure typical for the Myxilleae. with skeletal styles and diactinal dermal spicules; these latter, however, form a very dense dermal skeleton, and the species has oscular and pore-papillae; the other species of the genus has a similar construction, but the skeleton spicules have disappeared and the whole skeleton is formed of dermal spicules. 4 23 l-ORIFERA. III. Finally I may direct attention to the fact, that I have in the present work placed the genus Hymedesmia in the subfamily Ectyoninae, which perhaps might seem to go against the views given above about the relationship of this genus to the group treated here; yet this is not so, since firstly, the subfamilies Mycalinae and Ectyoninae, as I have already mentioned earlier, are scarcely quite natural, and even if so it was not impossible, that genera, which on account of their characters must now be placed in the Mycalinae , should be thought to have originally been derived from Ectyouiue forms. In the first part of this work I broke up Carter's Phloeodictyinac and placed its two genera Phloeodictyon and Oceanapia in the Renierinae and Gelliinae respectively. In a work published in 1905 (Rep. of the Pearl Oyster Fisheries of the Gulf of Manaar, Part III, 165) Dendy keeps the subfamily Phloeodictyinac under the family Desmacidonidae, and he refers to it the genera Phloeodictyon, Oceana- pia, Histoderma , Sideroderma and Amphiasfrc/la. His reasons for keeping these forms together are mainly the same as those of Carter on founding the group, viz. the hard dermal layer and the presence of fistulae, but on account of the chela; in Histoderma Dendy now removes the group to the Desmacidonidae. In Part I of this work pag. 56—57 I gave the reasons which seemed to me to necessitate the breaking up of the Phloeodictyinac, and the same reasons are still valid. While Dendy thus lays stress on the outer shape and the presence of a solid dermal layer as the distinguishing characters, but pays no attention to the spicules, I on the contrary follow the opposite way and take first, as the most important character, the spicules and what may be deduced from them with regard to the relationship of the forms. Dendy would also have difficulties in delimiting his subfamily; Phloeodictyon and Pctrosia are, as I have already declared (Part I, 1. a), nearly related; Thiele says (Zoologica XXIV, 2, 1899, 19) that Phloeodictyon (Rhizochalina) medium is an intermediate form; Melonanchora, which has a solid dermal layer and papillse should, I think, also be referred to the Phloeodictyinae and the same holds good with regard to several Hymcdcsmia-species; also some species of Gellius should be placed here according to the views of Dendy. On the other hand, I think that the spicules give good hints towards a natural grouping; the oxea present in Phloeodictyon are spicules typical for the Horn or r hap Ida c; Oceanapia and the species of Gellius, which are provided with a solid dermal layer, have oxea of quite the same kind, and these together with their microscleres refer them to the Heterorrhaphidae. The facts are quite otherwise with regard to the spicules in the four genera in question; their spicules are diactinal (when fully developed), but of quite another type from those occurring in the Homorrhaphidae and Heterorrhaphidae. That this is the case is shown, and beyond doubt, by the development, since while the spicules in Homorrhaphidac and Heterorrhaphidae are really diactinal, and also originate in this form, the spicules in the four genera mentioned are on the contrary only secondary diactinal, but originate as monactinal; they have thus a development quite as the dermal spicules in other Myxilleac. as I have described in Part II of this work, pag. 125. I therefore take it to be quite certain, that these genera belong to the Myxilleac, and that their spicules answer to the dermal spicules in the more typical Myxilleac, but here form the whole skeleton, of which the interior skeleton however is generally weak. The facts present in Melonanchora emphysema seem to me in the highest degree to confirm this view. The occurrence of chelae also shows that these genera have nothing to do with Phloeodictyon or Oceanapia: that the chela; may sometimes PORI1-ERA. III. 2q disappear does not invalidate the value of this character. -■ Dendy has also in his subfamily Phi dictyinae the genus Amphiastrella with the species birotulifera Cart.; this species has birotulse for miero- scleres and otherwise a structure almost the same as a Histoderma -- it shows especially a striking resemblance, both in outer shape and in structure, to Histodermella coriacea — ; this species certainly belongs to Iotrochota, but is a species in which only the dermal spicules are present, and if we form a special genus for it, this genus must be placed near to Iotrochota. After the manner in which I understand the classification of the above-mentioned forms, we will thus in the various families find the phenomenon, that certain forms have a specially developed dermal skeleton, as a rule together with a reduction of the inner skeleton and occurrence of longer or shorter papillae, by which these forms, in spite of their belonging to different families, get a certain mutual resemblance. It is then an obvious conclusion, that a common factor must be of influence but it seems not possible in our present state of knowledge to point out such a factor. It is easy enough to understand that all these sponges get provided with papilla;, since the hard dermal layer, furnished with close-lying spicules is not adapted to be pierced by pores and oscula and there must therefore be special contrivances for these, viz. the fistulse or appendages, and somewhat similar reasons hold good with regard to the reduction of the inner skeleton. But the cause of the development of the hard dermal layer is therefore not explained, and the only thing, that can be said, is that it seems to be in some connection with the fact, that these forms show a tendencv to get free, without attach- ment, or at all events without attachment by a fast-grown basis. The forms which are attached, either with a broad base as Histoderma physa, or by a peduncle as two of the /ufiale/la-species, have no specially strong dermal layer; in the quite free forms as most /Wat. N., 8° 26' Long. W., South of Jan Mayen, depth 371 fathoms (bottom temperature -=- or 4 C). One specimen. 36 PORIFERA. III. 3. G. carnosa Tops. PI. Ill, Figs. 20—21, PI. V, Fig. 4. 1904. Yvesia carnosa Topseut, Resultats des camp, scient. du Prince de Monaco, Fasc. XXV, 198, PI. XV, fig. 19. Plate-shaped and incnistiiig, or higher and more massive. Surface rugose and wrinkled, without projecting spicules. Oscula spout-shaped. The dermal membrane a thin film. The dermal skeleton formed of acanthoxea which are very scattered and often only found in the dermis in very small number. The main skeleton consisting 0/ fibres which from the base or the middle radiate towards the surface; there ore no transverse fibres, but the acanthoxea are scattered between the fibres. Sficula: mcgaselera : the skeletal spicules are polytylote tornota, irjy — o-j1/""", the dermal spicules acanthoxea o'ljJ—o-ijS"""; microsclera not present. The Ingolf-Expedition has taken three specimens of this species; one grows as a plate on a specimen of Biemma rosea and has a greatest extent of about 25 mm, and a greatest thickness of 311"", the second specimen grows on a shell of Pecten aratus as an incrustation with a greatest extent of 15"""; these specimens have thus in outer shape a resemblance with the specimens described by Topsent, which latter, however, reached to a greatest extent of 55""". ■ The third specimen is a small, oval body, of a length of 7rara; it has two oscular cones in one end, the other end shows a somewhat broken surface and besides some adhering bottom material; the specimen has thus probably been attached with this end and has thus been erect. The colour (in spirit) is lighter or darker brown, in one specimen quite white; Topsent's specimens were blackish, one or the other of the colours is certainly due to the action of alcohol. The consistency is somewhat firm and elastic. The surface, is somewhat wrinkled and folded, but otherwise smooth. The dermal membrane is thin but somewhat solid, it is not easily separable, and it is provided with spicules only to a very slight degree. Pores or pore- areas I have not seen, probably they are closed and must have disappeared in the folded and wrinkled dermal membrane. Of oscula as said two were found on one of the specimens, while the two others showed none. The skeleton. The dermal skeleton is in this species almost not developed, as there are, at all events in by far the most places, only rather few, scattered acanthoxea in the dermis. The main skeleton has a somewhat similar structure as in the other species; it consists of fibres which radiate towards the surface, are branched and support the dermis, but do not pierce it; the outermost fibres are as a rule thin, but here and there also very thick fibres go to the surface; in the interior the fibres are very thick and strong. The fibres go in the plate-shaped specimens not parallel from the base to the surface, but they seem to have a more or less extended centre at the base, from which they radiate to the surface; in the erect specimen there are thick spicular parts at the base and in the middle, from which fibres radiate out. There are no transverse connecting fibres, but acanthoxea are scattered between the fibres. The fibres consist of toruotes; the skeleton in the oscular cones are formed of fibres of toruotes, but no acanthoxea were seen here. Spongin was not observed. Spicula: a. Mcgaselera : 1. The skeletal spicules are tornota, they are straight, the ends are somewhat long-pointed, but outermost often a little stubby; they are distinctly polytylote. The length is 0-37— 0-47"™ and the diameter is between 0-005 an<^ o-ooy"111. The ends are generally not equal, but PORIFERA. III. 37 one is a little shorter and a little more stubby, the other longer and more pointed; the fine develop- mental stages are quite monaetiual, and the thinner spicules or developmental forms are generally more pronounced polytylote than the thicker. 2. The dermal spicules are acanthoxea, they are evenly curved, sometimes the curve forms an angle in the middle of the spicule; they are fusiform and long-pointed, tapering from the middle outwards. The spinulation is dense, the spines are largest in the middle but decrease in size outwards. The length is 0-137 — cri78mm and the diameter 0-004 " 0-007 mm. Some developmental stages were found, which were quite fine and more weakly spinulous. The tornotes form the fibres, the acanthoxea occur in the dermal membrane but much scattered, and besides they occur in the tissue, between the fibres. Microsclera are not present. I think it quite certain that this species is identical with camosa Tops., as the description answers precisely; the outer shape, the skeleton and the spicules agree, only the spicules are declared to be a little larger, the tornotes 0-53 — o-6omm with a thickness of 0-007— o-oion,m and tne acanthoxea o-i6— o-i8mm with thickness 0-005— o-oo6mm, but this difference is certainly of no consequence with regard to specific distinction; a fact which also contributes to the settlement that the species are identical is the communication by Topsent, that at the surface: "s'accumulent de large cellules spheruleuses a spherules dissociees, grosses, brillants. . .", since my specimens show the tissue at the surface filled with densely crowded, curious, rather large, elliptical granules ' |. Locality: Station 9, 640 18' Lat. N., 270 oo' Long. W., depth 295 fathoms; station 85, 630 21' Lat. N., 250 21' Loug. W., depth 170 fathoms; station 89, 640 45' Lat. N., 2 70 20' Long. W., depth 310 fathoms. The localities lie near to each other in the Denmark Strait. Gcogr. distr. The species has earlier been taken at the Azores at 380 46' Lat. N., 2 70 17' Long. W., depth 543 fathoms and 380 35' Lat. N., 280 06' Long. W., depth 664 fathoms (Topsent. 1. a). I shall here try to give a list of the Grayella species in the consecutive order in which they have been described, at the same time noting their spiculation and outer shape: Spicules : skeletal. dermal. microsclera. shape. 1862. G. rubiginosa O. Schmidt (Spong. d. adriat. Meer. 72, Taf. VII, Fig. 5) (Myxilla) tylota styli -f- crnst. 1864. — (ilbido. Bow. (Mou. Brit. Spong. II, 253, III, PI. XLV, figs. 21-24) (Hali- chondria) styli styli chelae arcuatse crust. 1869. — cyatopliora Cart. (Ann. Mag. Nat. Hist. 4, IV, 190, PI. VII) strongylotornota oxea -=- massive crnst. 1870. — papulosa O. Schmidt (Gruudziige einer Spongienf. Atl. Meer. 57) (Cn- brt'lla) strougyla oxea chelae arcuatae tuberous. t ') What these granules may be I cannot say; whether they really have something to do with Topsent's cellules spheruleuses is, I think, doubtful. ,3 PORIFERA. III. Spicules : skeletal. dermal. tnicrosclera. shape. 1876. G.pyrula Cart. (Ann. Mag. Nat. Hist. 4, XVIII, 388, PL XIV, fig. 20, PL XV, fig. 38) (Cometella) tornota styli chelae arcuatae club-shaped. 1882. — armigera Bow.1) (Mon. Brit. Spong. IY, 73, PL IV, figs. 10— 17) Hymenia- cidon) oxea styli chelae arcnatae crnst. 1885. — dura Arm. Hans. (Norw. North. Atl. Exp. XIII, 13, PL II, fig. 5) (Sclerilla) oxea oxea chelae arcnatae clnb-shaped. - arctica Arm. Hans. (ibid. 12, PL II, fig. 4, PL VI, fig. 15 (Sclerilla) . . . oxea oxea chelae arcnatae clnb-shaped. « — membranacea Arm. Hans.2 (ibid. 4, PL I, fig. 11, PL VI, fig. 12.) (Reniera) ? oxea ? ? 1892. — pedunculated Tops. (Resultats des camp. sc. du Prince de Monaco, II, 105, PL V, fig. 6, PL X, fig. 17.) (Yvesia). . tornota styli chelae arcnatae club-shaped. « — fallax Tops.{ibid., 106, PL VI, fig. 13, PL X, fig. 14.) .(Yvesia) tornota styli chela; arcuatae massive. « — Hanseni Tops, (ibid., 106, PL VI, fig. 9 a, PL X, fig. 13) (Yvesia) tylota styli chelae arcnatae, crust. sigmata - Ricliardi Tops, (ibid., 107, PL X, fig. 15.) (Yvesia) tylota styli chelae arcuatae, crust. sigmata « — Guen/ei Tops, (ibid., 105, PL III, fig. 7, PL X, fig. 16) ( Yvesia) styli styli sigmata thick crust. « — Ridley arcuattc 0-028 — o-ojo' .mm Of this species, whicli I refer to it. Koehleri Tops, (see below under remarks), we have a rather large material. The specimens form thin incrustations on stones, some single ones grow on tubes of Placostcgus tridental us The greatest extent to which my specimens reach is 24 mm; the thickness reaches scarcely 0-5 mni. The colour (in spirit) is generally white, sometimes a little darker and then greyish brown or light brown. The surface is in the undamaged specimens smooth, without projecting spicules, but under a good lens it appears finely gritty, which is caused by the styles. The dermal membrane is an easily separable, thin and transparent membrane; it is filled with rnicroscleres and is supported by scattered bundles of dermal spicules. Pores I have only observed with certainty in a couple of specimens, and in these they were seen as scattered, circular openings of a diameter of about 0047 n,m; when the pores are normally open they probably lie in groups over the subdermal cavities. Oscula could in several specimens be observed with a good lens. They are scattered on the surface and appear as very weakly pronounced and low cones of a diameter of about imm. In the centre an opening appears which is larger or smaller in relation to the degree of opening of the osculum; on account of the slight thickness of the sponge the opening only appears as a deepening; when the osculum is closed, the cone appears slightly stellately corrugated. The dermal spicules form an oscular skeleton, as they lie very close in the wall of the oscular cone and are arranged subparallel, so that they radiate stellately towards the oscular opening; above the dermal spicules, however, lies the dense layer of chelae; this layer is only wanting just at the very summit of the oscular cone. Larger and smaller subdermal cavities or canals may be seen shining through the dermis, especially in the lighter coloured specimens. The skeleton. The dermal skeleton may be said for the greater part to be formed of the chelse, which form a very dense layer in the dermal membrane. Moreover, short and loose fibres or bundles PORIFKRA. III. 43 of dermal spicules stretch, generally in a more or less oblique direction, from the- interior of the sponge out to the dermis; besides, they are also found in the dermis, below the layer of chelae, as scattered bundles or single spicules; finally they form, as said, the skeleton of the oscular wall, also lying here below the layer of chelae. The main skeleton is formed of the acanthostyli which all have the heads fixed on the substratum and are vertical; the largest acanthostyli reach with the point up to the dermal membrane, but in the undamaged sponges they scarcely project beyond it. The smaller styles are placed between the larger. Spongin was not observed with certainty. Spicnla: a. Mega sclera, i. The skeletal spicules are acanthostyli which are generally straight, sometimes slightly curved; they have a somewhat distinct head, and from this they taper evenly, thus forming a long apex which is often a little more abruptly pointed at the very point. The spinulation is somewhat dense in the lower part of the spicule, but becomes more scattered out- wards, and the outermost part is generally smooth; the longer the spicules are the point is to a greater extent smooth, and in the smaller spicules the spines are found quite out to the point. The spines are somewhat reclined. The head is densely covered with spines, which are considerably larger than the others, and also have a different shape; the}' are not reclined but more or less straight radiating, and they are as a rule not pointed but obtuse at the end; this obtuse or cut end is not rarely somewhat jagged or crenulated. The styles vary much in size and as the intermediate forms occur somewhat sparingly, the styles would seem divided into two groups with regard to size, but there is certainly no principal division into two groups. The length varies in all between 0-09 and 0'33m'1'1 and the diameter at the head, including the spines, varies from 0-014 — 0-035 '""'. With regard to the size of the styles there may be some difference in different individuals, in some the greatest length was thus 023""" and the diameter oo34n,m; when the spicules thus only reach a smaller length, the mentioned division into two groups is generally still less distinct. 2. The dermal spicules are rather slender, straight strongyla; the two ends are often a little different, one being slightly thicker than the other, and sometimes one or both ends are slightly swollen; in other cases the ends are somewhat narrowed. The strongyla are always polytylote with a row of swellings; this may be more or less pronounced, but is rarely or never quite wanting. The strongyla have a length of 0-196 — o-30n,m, and a diameter in the middle of 0-005 — 0*007 mm. These spicules do not vary much in the various individuals, b. Microsclera; these are chelae arcuatae; they have a more or less, but always rather strongly, curved shaft, the alae are lobe-shaped, the tooth is narrowly elliptical with the end rounded, and there is a long, narrow tuberculum. The shaft is not cylindrical but somewhat flattened, which may be present to a higher or lower degree. The chelae may vary a little in shape and size in the various individuals, the shape, however, is chiefly the same. The length is, all variations concerned, 0-028 — 0-050"""; as instances of variation in size in various individuals I may note the following: 0-028— 0*038 mm, 0*035— 0*042'"'", 0037— 0*045 mm and 0*032 — 0*050 "'"'; the diameter of the shaft is 0*004— o*oio",m in relation to the size of the chela, and to whether it is seen in front or side view. As said, the chelae occur in the dermal membrane forming a dense layer; they are also seen singly through the whole body. Remarks: I have determined the above species as H. KoehleriToips., but not without hesitation. When Topseut in 1896 founded the species, he laid stress especially on the polytylote strongyles, PORIFERA. III. but this is not a very safe character, as strongyles more or less polytylote are of frequent occurrence in Hymedesmia; already when he founded the species, Topsent mentioned, that it varies somewhat with regard to the spicules, and in 1904 he again states that this variation takes place to a high degree, the three forms of spicules varying both in size and in shape; according to this I am not at all sure, that all the specimens mentioned by Topsent belong really to the same species. When I have determined my species as Koelileri, my reason is especially the somewhat robust, conical acantho- styli, generally with large, somewhat obtuse or crenulated spines at the head-swelling, the polytylote strongyla with unequal ends and also the shape of the chelae. Now, as already stated, my specimens may also vary to a certain degree, and the acanthostyli are not always so robust, or with so large spines at the base as in the more typical specimens, and the possibility, that there may be more than one, very nearly related species in my material is not quite excluded. Locality: Station 9, 640 18' Lat. N., 2 70 00' Long. W., depth 295 fathoms; station 16, 65° 43' Lat. N., 260 58' Long. W., depth 250 fathoms; station 54, 630 08' Lat. N., 150 40' Long. W., depth 691 fathoms; station 57, 63° 37' Lat. N., 130 02' Long. W., depth 350 fathoms; station 98, 650 38' Lat. N., 26° 27' Long. W., depth 138 fathoms; further it has been taken East and West of the Faroe Islands in depths of 250 and 180 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902). The localities are situated in the Denmark Strait, between Iceland and the Faroe Islands and East of the latter. Geogr. distr. Topsent mentions the species from the Bay of Gascogne, depth 648 fathoms, and from the Azores in depths of 318 to 1350 fathoms. At present the species would thus be known from about 66° to 380 Lat N., and between about 2° and 310 Long. W., with a bathymetrical range from 138 to 1350 fathoms. 2. H. lacera n. sp. PI. V, Fig. 6. I in rusting ; surface smooth. Spicnla: megasclera; the skeletal spicules slender acanthostyli zuith a slightly marked head, spincd only in the lower half part, ovj — o'jji""*, not divided into hvo groups; dermal spicules large, generally slightly polytylote strongyla, 0'j2? — o-qj""" ; microsclera chela: arcuata> o-ojj — o-c>54""". Of this species one specimen grows as an irregular incrustation on a worm-tube which is attached to a Hornera lichenoides, another specimen grows on a mussel-shell; the greatest extent of the specimens is about i5mra, and the thickness is about 0-5 """ or a little more. The colour (in spirit) is whitish grey or dirty brownish grey, but it is stated to be light dirty green in the fresh state. The surface is smooth, without projecting spicules. The dermal membrane is a somewhat solid film. The skeleton. The dermal skeleton is formed of bundles or short fibres, stretching from beneath up to the dermis, upwards they are somewhat penicillately spread; moreover, bundles or somewhat longer fibres are found lying horizontally in the dermal membrane, and finally there are scattered chelse. The main skeleton is constructed in the ordinary way; the styli are very dispersed. So far as I could observe there is some spongin at the base. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli, which are very slender and straight or quite slightly, rarely a little more, curved; the head is generally only very slightly PORIFERA. III. 45 swollen, and the shaft tapers into a long, fine apex. The spinnlation is both in the large and in the smaller styli restricted to about the lower half part; in the small styli there are, however, generally- some scattered spines more apically. The spines are only somewhat large on the head, outwards they become small and still further outwards they are small grits, but generally more or fewer larger spines are found between them. The spines are directed straight out, not reclined. The length is 0-13 — 0-51 """, and the diameter of the head is 0014 — 0'025m'". The styli are not divided into two separate groups, but the intermediate sizes are rare. 2. The dermal spicules are rather large, straight strongyla; one end is generally a little thicker than the other, but this feature is not always distinct; the thicker end, or both ends may be quite slightly swollen; the shaft is slightly polytylote, but sometimes this is hardly apparent. The length is 0-327 — 0-47""", and the diameter 0-007—0-011""". b. Microsclcra, these are chelae arcuatse; they have an evenly, not specially strongly curved shaft; the tooth is narrow, lanceolate, the alse are of the same length as the tooth, but they are relatively narrow, they may therefore, in a certain view be of a somewhat claw-shaped appearance, and the chela may remind one somewhat of an ancora. The length is 0-045— 0-054 mm, the shaft is somewhat flattened, the diameter relatively from 0-0028 to o-oo57mm. The chelae occur rather numerously scattered in the dermal membrane. The slender, often straight styli, generally showing some large spines among the small, are characteristic for this species together with the large dermal spicules and the large chelae with relatively long, narrow alse. Locality: Station 113, 690 31' Lat. N., 70 06' Long. W., depth 1309 fathoms (bottom temperature -=-i°oC), one specimen; Forsblads Fjord in East-Greenland, 720 28' Lat. N., depth 50-90 fathoms (The Amdrup Expedition 1900), one specimen. The species must, according to these localities, be a native of the cold water. 3. H. storea n. sp. PI. V, Fig. 7. Incrusting; surface smooth/ Spicula: megasclera; tin- skeletal spicules somewhat densely spined acauthostyli with a globular head, the longer of them 7vifh a smooth apical part , owu—o-jo""", not divided into two groups; the dermal spicules polytylote strongyla vjij— u-j/""" ; microsclcra small chela arcuatce recalling in shape the palmate chelce, o'ojj — o'Oj8"tm. This species grows as extended but thin incrustations on stones; it reaches a greatest extent of 65mm, the thickness is very slight, below 0-5'""'. The colour (in spirit) is whitish grey. In the present state of the sponge the surface is densely and finely hispid, caused by the skeletal spicules, but this seems to be due to the fact, that the dermal membrane is wanting for the greatest part; where the membrane is present, the surface seems to be smooth. The dermal membrane is a thin membrane, resting on the skeleton below. The skeleton. The dermal skeleton ; the dermal spicules form a skeleton of bundles and fibres stretching from the basal skeleton up to the dermis; the fibres run more or less obliquely or bend horizontally under the membrane. The main skeleton is constructed in the ordinary- way, consisting of vertical acanthostyli not placed specially densely. At the base an amount of spongiu is present. 46 PORIFERA. III. Spicule: a. Megasclera. i. The skeletal spicules are acauthostyli, they are straight, more ly slightly curved, with a distinct, globular, but however only slightly swollen head. The spinu- lation is dense, consisting of large, more or less reclined spines; on the head, where the spines are largest, they radiate straight out, and also on the lowermost part of the shaft; the larger styli become dispersedly spined outwards and have a smooth apical part; the smaller ones are spined in the whole length, but they have often, however, the spines somewhat dispersed towards the apex. The length is cvio— 0-30 mm, and the diameter of the head is 0-014—0-028"""; the styli are not divided into two groups of size. 2. The dermal spicules are straight strongyla; they are of the same thickness in the whole length and more or less polytylote; one end may be quite slightly swollen. The length is 0-29 — 0-37""" and the diameter 0-005 — 0-007'"™. D- Microsclera are chelae arcuatae, they are rather small and slender, the tooth is narrowly elliptical, the alee are connected with the shaft in their whole length, viewed from in front they are only slightly incised below, the chela thus approaches to the palmate chelse; the shaft is slender and evenly but not much curved. The length is 0-033— 0-038 ",m, a"d the diameter of the shaft 0-002 mm. The chelae occur in somewhat great numbers in the dermal membrane. This species in its acauthostyli somewhat resembles Koehleri, but it has larger strongyla, and more slender chelse of another shape; from baculifera Tops, it is distinguished by the chela;. Locality: Station 105, 65° 34' Lat. N., 70 31' Long. W., depth 762 fathoms (bottom temperature -r- o° 8 C); station 125, 68° 08' Lat. N., 160 02' Long. W., depth 729 fathoms (bottom temperature -=- o° 8 C); the species is thus limited to the cold area. The localities lie North and North-east of Iceland. 4. H. lamina n. sp. PL V, Fig. 8. Incrusting; surface smooth. Spicula: megasclera ; the skeletal spicules acauthostyli with a rather small, globular head, spined in the wlwlc length, but the spines in the longer spicules very dispersed towards the point, 111111 Of this species we have five specimens, three growing on two different Bryozoa, one on a stone and one on a living Brachiopod; it has a greatest extent of 10 — ijmm, the thickness is about o-5mm. The colour (in spirit) is greyish white. The surface is smooth, without projecting spicules. The dermal membrane is a rather thin, but somewhat solid membrane, resting on the skeleton below. Some canals were seen shining through the membrane. The skeleton. The dermal skeleton consists of bundles and fibres of dermal spicules, stretching In mi the lower part of the sponge up to the membrane; they have a more or less oblique direction, and below the dermal membrane they may run as horizontal or nearly horizontal fibres, but there is no skeleton in the dermal membrane itself; the fibres have many spicules alongside, but they are however not specially thick. The main, skeleton is formed in the ordinary way, it is somewhat dis- persed. At the base an amount of spongin is found in which the heads of the acanthostyli are imbedded. PORIFERA. III. 47 Spicula: a. Megasclera. i. The skeletal spicules are straight or very slightly curved acanthostyli; the head is globular, but not however much swollen, the apex is long and evenly tapering; the spines are distinct also in the larger styli; the small styli are entirely spined, in the larger the spines are very dispersed towards the point, but they are most often present out to the point, or only a small part of the apex is smooth; more rarely the styli may be smooth for a longer distance. The length is o-i2— 0-33 mm, and the diameter of the head is 0-012- 0-022 """. 2. The dermal spicules are straight strongyla; they are of the same thickness in the whole length and slightly polytylote; the length is 0-22 — 0-36 mm and the diameter about 0-005 mm. The size of the megascleres may vary a little in various individuals, b. Microsclera; these are chelae arcuatse; they are small and of a particular shape, by which they approach somewhat to the chelse palmatse; the shaft is evenly curved, the tooth is lanceolate, and the alse are connected with the shaft in their whole length, it is therefore chiefly only the curved shaft which distinguishes them from the palmate chelse. The length is 0-028 """ and the diameter of the shaft about 0-002 mm. The chelse occur scattered in the dermal membrane. This species is characterised already by its chelse. Locality: Station 1, 620 30' Lat. N., 8° 21' Long. W., depth 132 fathoms; station 25, 63° 30' Lat. N., 540 25' Long. W., depth 582 fathoms; at Angmagsalik on the East coast of Greenland, depth 140 fathoms (The Amdrup-Expedition 1900); 6i° 40' Lat. N., 7° 40' Long. W., depth 135 fathoms (Ditlevsen); East of the Faroe Islands, depth 250 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902). The localities are situated in the Davis Strait, at East-Greenland and at the Faroe Islands. 5. H. mollis n. sp. PI. VI, Fig. 1. Incrnsting ; surface smooth. Spicula: megasclera; the skeletal spicules acanthostyli with a small head, the larger slightly spined and smooth outwards, the smaller spined in the whole length. 0-119— °'52>"""- ""f divided into two groups: the dermal spicules strongyla 0-24 — o-jjj""",- microsclera chela arcuatoe 0-027 — 0-040""". Most specimens of this species grow incrusting on Brachiopods, as well on living as on dead specimens, one grows on a shell of a Buceiiium, one on a mussel-shell and finally one on an Oculina. The greatest extent measured is about 20mm; the thickness generally does not exceed 0-5""". Two speci- mens grow in a remarkable manner; they are not attached to a definite substratum but grow on sand, gravel and small particles of very different kinds, especially sponge-spicules; they then envelop the substratum, so that the sponge together with the substratum forms irregular, wrinkled masses which seem rather thick, but the real thickness is not greater than given above. The colour (in spirit) is greyish brown. The surface is smooth or nearly so. The dermal membrane is a thin film, but it is for the greater part wanting on the specimens. Oscula ami pores were not to be observed on account of the bad condition of the dermal membrane. The skeleton. The dermal skeleton: the skeleton formed of the dermal spicules is strongly developed. Quite down at the base of the sponge the dermal spicules form fibres or fibre-like bands 48 PORIFERA. III. running parallel with the underlayer; further there are bundles stretching obliquely up to the surface, and at the surface there are again bundles or fibres present running more or less parallel with it; besides, there are also found scattered spicules at the surface. The bundles are often rather thick. The dermal spicules form thus the greatest part of the whole skeleton. The main skeleton consists of acanthostvli with their head-ends on the substratum; they do not reach beyond the surface. Spongiu seems to be found at the base, but only to a very slight degree. Spicula : a. Megasclera. i. The skeletal spicules are acanthostvli; they are straight or slightly curved and have a rather small head-swelling; the apex is even and long. The spinulation is somewhat slight, as commonly the largest spines are found at the head-end; in the longer styli the spines become very small outwards, and the outer part of the spicules is smooth; the smaller styli are spined in the whole length, and the spines are generally larger. The styli vary much in size, but the}- are not divided into two groups. The length is 0-119 — °'53mm anc^ the diameter of the head 0-014— 0-027 mm. 2- The dermal spicules are strongyla, they are straight or, more rarely, slightly curved, and they are slightly fusiform. The ends are not uniform, one end is rounded and sometimes slightly swollen, the other end is thinner and rounded or with a stubby point. The length is 0-24— 0-357 mm and the diameter about 0-004— o-oo57mm. The strongyla may be slightly polytylote on the middle part. b. Micros cler a ; these are chelce arcuatse; they have a curved shaft, the curvature of which is distinctly situated in the middle of the shaft; the end-parts occupy nearly always less than a third part of the length of the chela; the tooth is broadly elliptical, the alse are lobe-shaped, of the same length as the tooth. The length may vary somewhat in the same individual and still more in various individuals, it is in all 0-027 — 0-040 mm, a°d the diameter of the shaft is 0-0028— o-oo4n'm. The chelae occur rather numerously in the dermal membrane, and they seem exclusively or at all events chiefly confined to it. Locality: Station 25, 630 30' Lat. N., 54° 25' Long. W., depth 582 fathoms; station 28, 650 14' Lat. N., 550 42' Long. W., depth 420 fathoms; station 83, 620 25' Lat. N., 280 30' Long. W., depth 912 fathoms; station 97, 650 28' Lat. N., 27° 39' Long. W., depth 450 fathoms; further it has been taken at 640 42' Lat. N., 270 43' Long. W., depth 426 fathoms (Wandel), 620 29' Lat. N., 50 17' Long. W., depth 160 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902) and 63° 05' Lat. N., 200 07' Long. W., depth 295 fathoms (The Fishery investigation steamer "Trior"). Nine specimens in all. The localities are situated in the Davis Strait, the Denmark Strait, South of Iceland and West of the Faroe Islands. 6. H. curvichela n. sp. PI. VI, Fig. 2. Incrusfiug; surface diffusely hispid. The main skeleton not dense. Spicula: megasclera; the skeletal spicules acaufhos/yli with no distinct or only a slight head; flic small spined in the whole length. the larger less s fined unfit m/ly spined at the base; the styli divided into fzco groups, large /rjj—o-So""", small 0'ioy — 0-30""" ; the dermal spicules strongyla, slightly polytylote. f the specimens of this species one grows on a stone together with If Koehleri, baculifcra P0R1FERA. III. 49 Tops., dubia n. sp. (to be described hereafter), a Plocamia, an Eurypon and a Polymastia; another speci- men is sitting on a Pccten-sheW, likewise covered with several other species, a third specimen grows on a Brachiopod-shell and finally a fourth on an erect Bryozoon. The species forms incrustations of a greatest extent of 25 mm with a thickness of about 0-5 mm. The colour (in spirit) is white or whitish, but with regard to two of the specimens it is stated, that they were deep blue in the living state. The surface is diffusely hispid from rather long projecting spicules. The dermal membrane is a thin and transparent film. Pores and oscula were not observed; some canals or canalicular cavities were seen to shine through the membrane. The skeleton. The dermal skeleton; in the dermal membrane there are numerous, but some- what scattered chelse. The dermal spicules form fibres or bundles stretching far down in the skeleton and seen quite down at the base; they stretch in an oblique direction up to the dermal membrane, and above, at the membrane the direction becomes nearly quite horizontal; some spicules are also lying singly, quite horizontally in the membrane. Above, at the membrane the bundles are generally rather strong with numerous spicules. The main skeleton is of the typical construction and consists of basal acanthostyli with the head ends attached to the substratum, the longest styli pierce the dermal mem- brane and project beyond it. The skeleton is distinguished by the fact that the styli stand somewhat scattered, considerably more scattered than is commonly the case. At the base there is a distinct amount of spongin, in which the heads of the styli are imbedded; the spongin seems to form a con- tinuous lamella at the base of the sponge. Sfiicula: a. Megasclera. 1. The skeletal spicules are acanthostyli which are straight or, especially the larger ones, slightly curved; they have generally no distinct head marked off, or this is only the case to a slight degree, but the dense spinulation at the base gives however the impression of a swelling; they taper evenly into a somewhat fine apex. The spinulation is as usual, the spines being largest at the head-end and radiating, while they are generally reclined on the shaft in the smaller styles. The smallest styles are spiued in the whole length, the longer the styles are, the longer a part of the apex is smooth, in the longest styles only the lowermost part is spined, and the spines are here generally small, nearly gritty, and not reclined. The size of the styles varies greatly, the length from 0-107 to about o-8ommI and the diameter of the head is from o-oi8— 0*034 mm. To be sure there is no principal difference between the styles, but there is a break in size between the longest and those coming next in length, such that the longest do not go below 0-53 mm and the small not beyond o-30mm. 2. The dermal spicules are rather long, straight, slightly polytylote strongyla; they have always one end thinner than the other; the length is 0-32— o-4omm, and the diameter in the middle is about 0-005— 0-007 mm. b. Microsclera ; these are chelse arcuatse; they are distinguished by the shaft being strongly, nearly semicircularly curved; there may in this respect be some difference, the chelae may be both more or less curved, but the typical form is near the semicircular curvature; the end parts are relatively small, the tooth and the alae are short and rounded. The length is 0-031 — 0-03 7 nim; the shaft is somewhat flattened and about elliptical in section, its diameter is, as seen from in front or from the side respectively 0-005— o-oiomm. The chelse occur, as mentioned, numerously in the dermal membrane, but, however, somewhat scattered; they were not observed otherwise in the body. x) The greatest length cannot lie given exactly, as these styles generally have the apex broken. The IngolMvxpeilition. VI. 3. 7 t-Q PORIFERA. III. This chela bears, in its mostly curved forms, strange to say, great resemblance to the chela found in a species standing rather remote, viz. the chela figured by Carter (Ann. Mag. Nat. Hist. 5, XV, PI. IV, figs. 3 e, f.). Carter figures also a developmental stage (d), but considers this as an "ill- developed" spiculum. Locality: Station 15, 66° 18' Lat. N., 25° 29' Long. W., depth 330 fathoms (bottom temperature -f-o°75C); station 89, 64° 45' Lat. N., 27° 20' Long. W., depth 310 fathoms; both these localities lie in the Denmark Strait; further it was taken East of the Faroe Islands, depth about 250 fathoms, and West of the Faroe Islands, depth 160 fathoms, (Ad. Jensen, the cruise of "M. Sars" 1902). Four speci- mens in all. It is curious that one of the localities, station 15, shows a negative bottom temperature, while the other localities are positive, but it is to be remarked, that this station lies just at the border between the cold and the warm areas. 7. H. rugosa n. sp. PI. Ill, Fig. i, PI. VI, Fig. 3. Incrusting ; surface somewhat wrinkled, smooth; oscula present as very lozv cones, with a dense skeleton of dermal s picnics in the wall. Spicula: megasclera; the skeletal spicules acanthosfyli with a slight head, spined in the whole length, divided into two groups, large o-jo — o-jsq""", small ovj — o-/pm'"; the dermal spicules poly tylote strongyla o-ji — 0-417"""; microsclera targe chela' arcuatce with the ends a little recurved, 0-052 — 0-064""". Of this species we have two specimens, one growing on a Brachiopod-shell, the other 011 a worm-tube. The sponge forms thin incrustations, which reach a greatest extent of 17 mm, with a thickness not exceeding 0-5 mm. The colour (in spirit) is yellow or light brownish. The surface is strongly wrinkled and rugose, the dermal membrane being folded, thus giving rise to the formation of irregular, sinuous furrows; this appearance is probably owing to contraction; for the rest the surface is smooth without projecting spicules. The dermal membrane is a somewhat solid, easily separable membrane, richly crowded with chelae. On one of the specimens two oscula are seen; these have a structure similar to that of the oscula in H. Kochleri, they show in the centre a circular or oval impression, around which the dermal membrane forms stellately radiating folds; the dermal spicules form here a special skeleton, lying close together in the oscular wall with one end towards the opening, and from this radiating out in the membrane. The diameter of that part of the membrane which may be termed osculum is 1-5 — 2mm. Pores were not to be seen in the membrane which is so densely charged with chelae. The skeleton. The dermal skeleton; the dermal skeleton proper is formed of the chelae which are extremely close-lying in the membrane; when they are so close-lying, this is perhaps due to contraction. The dermal spicules partly contribute to the formation of the other skeleton of the sponge, as they form bundles or fibres, stretching from the very base up to the dermal membrane, generally in a very oblique direction; in many places they also form horizontal fibres just below the membrane; finally they form, as mentioned, the skeleton in the oscular wall. The fibres and bundles formed of the dermal spicules are rather thick. The main skeleton is of the typical construction, and PORIFERA. III. $1 consists of vertical acanthostyli with their heads based on the substratum; the longest of them reach the dermal membrane, but do not pierce it. Just at the base of the sponge there is, I believe, a slight amount of spongin, but I was not able to see it with absolute certainty. Spicula: a. Megasclera; i. The skeletal spicules are straight or slightly curved acanthostyli; they have a slightly swollen head and taper evenly into a long apex which outermost is a little more abruptly pointed. The spines on the head are large, they are not pointed but truncate and not rarely somewhat hook-shaped. The spines on the shaft are somewhat dense and continue out to the point, but they are more scattered in the outermost part; the spines are reclined and compressed, so that they get the shape of a tooth of a saw. The styli vary greatly in size, and as intermediate forms are very scarce they are divided into two groups, which are, however, not quite sharply limited. The length lies in all between 0-15 and 0-429""", and the diameter of the head is 0-025— 0-040'""'. When the single intermediate sizes are not considered the two sizes will be about 0-15 — 0-19""" and 0-30 — 0-429""". 2. The dermal spicules are slender, straight, or more rarely slightly curved, polytylote strongyla, the ends are generally slightly swollen, so that the spicules approach to subtylota; one end is as a rule a little thicker than the other, and the thinner end has the largest swelling; the swellings are the more distinct the thinner the spicule is, in the thickest strongyla they are very slight or quite- wanting. The strongyla vary somewhat in size, the length is between 0-31 and 0-417""", and the diameter is 0-005— 0-008""". D- Microsclera are chelae arcuatte; they have a curved shaft and the ends are somewhat recurved; the tooth is lanceolate, with a long tuberculuin, and the alae are of the same length as the tooth; the shaft is somewhat flat, and nearly always slightly dilated in the middle. The chela is rather large, and the size is somewhat constant, the length is 0-052 — 0-064""", and the diameter of the shaft varies from about 0-005 — o-on""" in relation to the chela being seen in front or in side view, and to the dilatation in the middle of the shaft being larger or smaller. Single develop- mental stages were seen. The chelae occur, as said, in enormous numbers and densely crowded in the dermal membrane, and they do not seem to occur otherwise in the body of the sponge. Locality: Station 9, 640 18' Lat. N., 270 00' Long. W., depth 295 fathoms. Two specimens. The locality lies in the Denmark Strait. 8. H. splenium n. sp. PL VI, Fig. 4. Incrusting; surface hispid. Spicula: megasclera; the skeletal spicules densely and entirely spined acanthostyli with a very slightly marked head, divided into two groups, large o-2j — 0-27""". small o-op — o-i2"""; the dermal spicules strongyla 0-25— o-ji""" ; microsclera chela arcuatm 0-041 — o-oj?""". This species grows as rather extended incrustations on a somewhat large stone; it has a greatest extent of about 16""", the thickness is small, below 0-5""'". The colour (in spirit) is whitish grey. The surface is dispersedly hispid from projecting skeletal styles, and it seems to be so also when the dermal membrane is undamaged. The dermal membrane is a thin film, resting on the skeleton below. Here and there larger and smaller openings for the canal system were observed, partly placed in groups; they are probably both pores and oscula. r c2 PORIFERA. III. The skeleton. The dermal skeleton ; the dermal spicules form partly bundles, partly they are also seen lying scattered; they lie horizontally or stretch obliquely upwards between the ends of the skeletal styli, without any regularity; they lie horizontally especially just below the dermal membrane, and when the sponge is viewed from above, the spicules are seen lying irregularly below the membrane. The main skeleton consists of vertical, somewhat densely placed acanthostyli, the longest of which project beyond the surface. At the base a slight amount of spongin is found. Spicula: a. Mcgasclera. i. The skeletal spicules are straight acanthostyli; the head-end is (inly pronounced to a very slight degree, and the styli are therefore somewhat club-shaped. The spinulation is dense and is both in the small and the large forms continued quite to the point, or the spines are at most a little more dispersed towards the point; the spines are directed downwards; they are distinct but not large. The length of the styli is 0-09— 0-27 mm and the diameter of the head 0-015 — 0-024 mm. Though the styli do not vary much in length in all, they are divided however into two groups, the larger ones not going below 0-23"™ and the small not beyond o-i2mm. 2. The dermal spicules are straight strongyla, they are always a little thicker at one end than at the other, but they are otherwise of the same thickness in the whole length; sometimes they are very slightly poly- tylote. The length is 0-25 — 031 mm and the diameter 0-005 — 0-007 """. b. Microsclera ; these are chelae arcuatae; they are of ordinary shape, the shaft is evenly curved, the tooth elliptical, the ake lobe- shaped and broadly cut below. The length is 0-041— 0-04 7"' m and the diameter of the shaft is 0-003 — 0-004 mm. The chelae occur numerously in the dermal membrane, but not, however, forming a layer. This species is somewhat related to H. storca, but it is characterised by the styli being more densely spined, and spined to the very point, and the spines are smaller; besides, the styli are divided into two groups; the chelae are of another ] shape, and finally also the dermal spicules show a difference. Locality: Station 125, 68° 08' Lat. N., 160 02' Long. W., depth 729 fathoms (bottom temperature -f- o° 8 C); the locality lies North of Iceland. 9. H. tenuicula n. sp. PL VI, Fig. 5. In crusting; surface someivhat hispid. Spicula: mcgasclera ; the skeletal spicules acanthostyli zuith a slightly swollen head and divided info two groups, large, with the apical part slightly spined or smooth, 0-286— 0-47""", small, spined in the whole length, 0-12 — o-i$""" ; dermal spicules strongyla 0-238— 0-3 1'"'"; microsclera chelce arcuatm 0-032 — 0-037'"'". Of this species we have four specimens growing as thin incrustations on a Hamacantha impli- cans, on a Brachiopod-shell, on a tube of Placostcgus tridentatus and finally on a stone, bearing a specimen of Petrosia crassa; the largest specimen grows on the Brachiopod-shell, and it reaches the same extent as this, viz. 25 mm, but for the rest it grows on both sides of the shell which it thus quite covers. The sponge is very thin, scarcely reaching more than 0-25""" in thickness; this is, as will be seen below, less than the length of the largest styli, which consequently project beyond the surface. The colour (in spirit) is slightly yellowish. The surface is distinctly hispid on account of the projecting of the longest styli. The dermal membrane may be traced as a thin film, supported by the dermal spicules. Pores and oscula were not to be seen. PORIFERA. III. 53 The skeleton. The dermal skeleton consists partly of bundles of dermal spicules which stretch up to the membrane from the skeleton below, partly and chiefly of spicules lying horizontally in the membrane; the latter spicules are partly scattered, partly collected into bundles or short fibres. The main skeleton is formed of vertical acanthostyli, the shorter of which reach to the surface, while the longer project through it. At the base of the acanthostyli there is found an amount of spongin, but it is difficult to observe. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli, they have the head-end slightly swollen and taper from here into a long apex. The styli are divided into two sizes which are to be sure not connected by transitional forms, but do not show, however, any principal difference in shape. The larger styli are straight or slightly curved; they have a densely spined head, the spines are here not pointed, but truncate or irregularly cut at the apex; on the lower part of the shaft the spines are still somewhat dense, but they are small, outwards they become more scattered, and the outermost part is smooth or has only some single spines; the spines on the shaft are reclined. The small styli are likewise straight or very slightly curved, they are spined in the whole length, and the spines are reclined; the head is most densely spined. The length of the large styli is o-286 — 0-47 n,m with a diameter at the head of 0-028'""'; the greatest length is only rarely seen; the small styli are 0-12—0-15"'"' long and o-020mm thick at the head. 2. The dermal spicules are straight strongyla, one end is a little thinner than the other, and this thinner end is often slightly swollen; the length is 0-238 — 0-31 mm and the diameter about 0*004 mm. D- Microsclera; these are chelae arena tse; they have an evenly curved shaft, an elliptical tooth and lobe-shaped alse of the same length as the tooth ; the free middle part of the shaft is not much more than the third part of the total length of the chelae. The length is 0-032—0-037""", and the diameter of the shaft is about 0-004"'"'. The chelae are • found in the dermal membrane, generally they are scattered, sometimes lying more densely. This species is distingushed from H. storea by its more slightly spinulous acanthostyli which are divided into two groups, and by a different shape of the chelae. Locality: Station 1, 62° 30' Lat N., 8° 21' Long. W., depth 132 fathoms; station 35, 650 16' Lat N., 550 05' Long. W., depth 362 fathoms; station 98, 650 38' Lat. N., 260 27' Long. W., depth 138 fathoms; and Last of the Faroe Islands, depth 250 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902). The localities are situated in the Davis Strait, the Denmark Strait and East and West of the Faroe Islands. 10. H. similis n. sp. PI. VI, Fig. 6. Incrusting; surface smooth. Spicula: megasclera; the skeletal spicules acanthostyli with the small styli are 0-119 — 0-26""" long, with a diameter of the head of 0-020— 0-025 mm. Small individual variations in size may occur. Developmental stages of both sizes of the styli were seen in small numbers, showing that the two sizes are essentially different from the beginning. 2. The dermal spicules are tornota with intermediates to oxea; they are straight and long tapering; they vary a good deal in thickness, when they are thin they may be termed tornota, but often they are more fusiform and are then oxea; their length is 0-34 — 0-44 mm with a thickness of 0-008— 0-013 mm. Besides these spicules there are some stronger, especially thicker, and fusiform oxea of a length of 0-38 0-50""" and with a thickness in the middle of 0-017— 0*028 mm. — With regard to these latter spicules the facts are somewhat curious; they are mentioned both by Bowerbank and by Topsent, and both authors say, that they are present only in small numbers. But they seem to be subjected to great variations with regard to the number in which they are present; generally they are only found in very small numbers, and such is the case in most of my specimens; but in one specimen they are very numerous; whether they are few or many they are always only present in the dermal membrane, and lying horizontally, but they are not found in the bundles which stretch down into the sponge; in the specimen mentioned, with numerous thick oxea, the horizontal spicules in the dermal membrane are almost all of this kind; as the skeleton in the wall of the papillae is formed both of the spicules lying in the membrane itself, and of those belonging to the fibres stretching up into the wall, the skeleton of this latter consists consequently outwards of thick oxea, but inwards of thin ones. In the specimen with numerous thick oxea these are at the same time thicker and upon the whole larger than in the other specimens. — Develop- PORIFERA. III. 69 mental stages of the dermal spicules were seen in small numbers, they show that these spicules are diactinal from the first beginning, b. Microsclera; these are chelae arcuatae; they have an evenly curved shaft, the terminal parts are relatively small, and the alae are somewhat triangular; the length is 0-034— 0-040 mm; the shaft is not cylindrical but a little flattened, the thickness is in relation to this 0-003— 0-005""". The chelae occur through the whole sponge and outermost in the dermal membrane; they are especially numerous in the pore-membranes. Locality: Station 18, 61° 44' Lat. N., 30° 29' Long. W., depth 1135 fathoms; station 46, 6i°32'Lat. X., nc 36' Long. W., depth 720 fathoms; station 64, 620 06' Lat. N., 190 00' Long. W., depth 1041 fathoms; station 85, 630 21' Lat. N., 250 21' Long. W., depth 170 fathoms. The localities are situated in the southern part of the Denmark Strait, South of Iceland and between Iceland and Faroe Islands. Geogr. distr. The species was described by Bowerbank from .Scotland, depth 96 fathoms; Top- sent 1. c. records it from the Azores in depths of 448, 620, 756 and 1200 fathoms. It seems thus to have a very wide bathymetrical range, from 96 to 1200 fathoms. 22. H. simillima n. sp. PI. Ill, Fig. 7, PI. VII, Fig. 9. I nerustiiig ; surface smooth, bearing small oscular papilla and very low, poriferous zvarls, both with a dense skeleton of dermal spicules in the wall. Spicula: megasclera; the skeletal spicules acantho- styli with a small or no marked head, divided into two groups, large, only spiued at the base, irji — 0-65""", small, nearly spiued in the whole length, u-/6—u-/q"""; the dermal spicules oxca with inter- mediates to toruota, 0^2—0-47"""; microsclera strongly curved chela; arcuatce 0-028 — o-ojy""". Of this species we have several specimens of various sizes, growing on larger and smaller pebbles, shells, Brachiopods and tubes of Placostegus tridentatus. They are present in the material in all sizes from quite small up to an extent of 3on,in; the thickness is at most 07™"'. The colour (in spirit) is white to greyish white. The surface is smooth, without projecting spicules; other- wise it may have a somewhat wrinkled appearance on account of the papillae and impressed areas to be mentioned hereafter. The dermal membrane is a thin, but distinct and separable membrane; it rests on the skeleton below and is densely filled with chelae, but has no proper skeleton of horizontal dermal spicules. Oscula and pores: in the somewhat large and well developed specimens oscula are always found, they are conical papillae with a simple opening at the summit. The pores are also limited to certain areas, which may be described as very low, broad warts, somewhat recalling the structures in Inflatella viridis. They are bounded by a low wall, being generally lower on one side than on the other, the wart lying down towards the surface; the pore-membrane closes the opening and forms a sieve, it is densely filled with chelae. The pore-areas may be of various, generally relatively large diameters, up to 3™"'. When the sponge is examined with a lens, the pore-areas are only seen with difficult}-; as they are so very low the pore-membrane is always sunk down on the tissue below and the pores not to be seen, and therefore the only thing seen is a circular, depressed area, surrounded by a sharp edge. The skeleton. The dermal skeleton ; the dermal spicules form bundles and short fibres stretching _Q PORIFERA. III. from the main skeleton, often almost from the base, upwards to the dermal membrane which rests on them; above they are more or less penicillately spread; they are somewhat perpendicular or more oblique and often somewhat decumbent. The skeleton in the wall of the oscular and pore-papillae is formed by fibres stretching up in the wall and here forming a skeleton of close-lying, parallel spicules. There is no skeleton of horizontal spicules in the membrane, but this is provided with dense-lying chelae. The main skeleton is of the typical construction formed by vertical acanthostyli with their heads placed on the substratum; the longest of the styli may reach to or near to the surface. Spongin is present at the base, but only to a very slight degree. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli which are divided into two rather well defined groups of sizes. The large styli are straight or generally slightly curved near the head, this latter is small or not at all pronounced; the spines are only present on the head and a little way out, being here smaller and soon quite disappearing. The small styli are straight, the head is very small and for the greatest part due to the somewhat longish, radiating spines; the style is spined nearly in the whole length, only a small apical part being smooth; the spines are often reclined; they are of moderate size or small, and in this respect there may be some difference in different specimens. The length of the large styli is 0-41— cr65ram with a diameter of the head of 0-020— 0-028'"™, and of the small styli 016— o-io,mm and the thickness of the head about o-02imm. 2. The dermal spicules are oxea with transitions to tornota; they are straight and generally more or less fusiform and somewhat long tapering and in this case they are oxea, the thinner ones are more cvlindrical with shorter points and must be termed tornota. The length, which may vary a little in various specimens, is on the whole 0-32 — 0-47 mm with a diameter in the middle of 0-006— 0-014""". The spicules have generally not quite equal ends, but one end is slightly thinner than the other; the thinner the spicule is the more pronounced is this difference, and some few very fine developmental stages were quite monactiual, thus showing that the spicule begins as monactinal. Besides the mentioned dermal spicules there are also in this species, as in the preceding one, some thicker, fusi- form oxea, they have a length of 0-29 — 0-35™"' with a thickness in the middle of 0-015— 0-017'"'"; they are very scarce, and as the measurements show, they seem to be connected in size with the ordinary spicules, only being specially short and thick, and in contrast to the case in the preceding species they are here shorter than the ordinary dermal spicules. So far as I have seen, these thicker spicules are found in the outer part of the fibres, just at the dermal membrane, b. Microsclera ; these are chela? arcuatae; they have a strongly, sometimes semicircularly curved shaft, the alee are lobe-shaped, and short and round; the length is 0-028— 0-037 mm, the most strongly curved may sometimes be a little shorter; the shaft is somewhat flattened, its thickness is in accordance herewith 0-004 — 0-007 mm; developmental stages were seen in small numbers. The chelae are seen through the whole sponge, but only in small numbers, in the dermal membrane the)' form on the other hand a more or less dense layer, and they are numerous in the pore-membrane. This species is rather similar to and seems also nearly related to H. occulta, but it is charac- teristically distinct; as to the skeleton it is distinguished by the absence of a proper dermal skeleton, and with regard to the spicules the chelae have a different shape and are much more curved; also the difference in the development of the dermal spicules with diactinal beginning in one and monactiual PORIFERA. III. 71 beginning in the other species is to be noticed. - I think it verv probable, that the specimens mentioned by Topsent (1. c.) from stations 600 and 899, and which the author refers with some doubt to H. occulta, belong to the present species, as he declares the spicules to be somewhat smaller, and especially as he observes, that the chela? are more curved than in the typical occulta: his figures belong on the contrary certainly to occulta. Locality: Station 9, 640 18' Lat. N., 270 00' Long. W., depth 295 fathoms; station 54, 63°o8' Lat. N., 1 50 40' Long. W., depth 691 fathoms; station 85, 630 21' Lat. N., 250 21' Long. W., depth 170 fathoms; station 98, 65° 38' Lat. N., 260 27' Long. W., depth 138 fathoms; further it has been taken East of the Faroe Islands, depth 250 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902), at 66° 20' Lat. N., 250 12' Long.W., depth 96 fathoms (Wandel), and at Augmagsalik in East Greenland, depth 140 fathoms (The Anidrup Expedition 1900). The localities are situated at East Greenland, West and South of Iceland and East of the Faroe Islands; the bathymetrical range goes from 96 to 691 fathoms. If the species mentioned by Topsent with more curved chelae and smaller spicules should prove to be the present species, it has also been taken at the Azores in depths of 185 and 106 fathoms. Remarks: The two species H. occulta and simillima show great resemblance, and they might be thought nearly related if it were not for the difference in the manner of development of the dermal spicules. The existence of this difference is very interesting, but it is not, however, possible to decide for the present its real importance. -- The occurrence of special dermal spicules besides the ordinary ones is also an interesting fact; these spicules seem to be only extreme variations of the ordinary form, and we have then here again a fact, showing that the spicules placed outermost in the sponge may be liable to special variations, such as I have pointed out more particularly in Part II of this work (p. 32 — 33); also the difference in the abundance of these spicules in different specimens of the same species, as shown by occulta, has its parallel, as mentioned at the place cited. 23. H. baculifera Tops. PL VIII, Fig. 1. 1901. Leptosia baculifera Topsent, Arch, de zool. exp. et gen. 3, IX, 354. 1904. — — Topsent, Resultats des camp. sc. du Prince de Monaco, Fasc. XXV, 191, PI. XV, fig. 2. Incrusting; surface zvifhout projecting spicules. Spicula : megasclera; the skeletal spicules acantho- styli with a distinct head-swelling, spiued in the whole or nearly the whole length, o-oyj — 0-214'""' . not divided into two groups; the dermal spicules strongyla varying to subtylota uwj — 0-238""" : microsclera small chehe arcuatcv 0-021 — 0-025""". This species forms very thin incrustations on stones and on tubes of Placostegus tridentalus and other serpulid tubes. The greatest extent to which any of the specimens reach is 38mm, and the thickness is about 03 mm. The colour (in spirit) is whitish to brown. The surface has no projecting spicules, but seen with a lens it is finely gritty, caused by the skeletal styli. The dermal membrane is a thin film, it is filled with microscleres and supported by dermal spicules. Oscula and pores I was not able to detect. _2 PORIFERA. III. The skeleton. The dermal skeleton. Besides the chelae filling the dermal membrane, this is supported by bundles of dermal spicules, which stretch upwards from the main skeleton; further some scattered spicules are present in the membrane. The main skeleton consists as usual of vertical acanthostvli with their head-ends fixed on the substratum. The longest of the styli reach to the dermal membrane, but without projecting through it. A slight amount of spongin seems to be found just at the substratum, but it is at all events difficult to observe. Spicula: a. Megasclera. i. The skeletal spicules are acanthostvli; they are straight or slightly and evenly curved; they have generally a somewhat distinct head-swelling, and they taper from the head into a long apex, which may be more shortly pointed outermost. The spinulation is dense in the lower part of the style, but it is more dispersed outwards; in the longer spicules an apical part is smooth, while the shorter ones are spined to the point. The spines on the shaft are reclined, on the head they are placed more densely and are longer, radiating straight out and generally truncate. The acanthostvli vary much in size, but they are not divided into two groups. The length is 0-077 — 0'2i4mm, and the diameter at the base is o-on — 0028™"'. In some specimens the styli did not reach beyond o-i78mm. 2. The dermal spicules are strongyla varying to subtylota; they are straight, sometimes a little polytylote but only to a slight degree. The ends may be simply rounded but they are most frequently slightly swollen; they are not equal, one being a little thinner than the other, and this thinner end shows the most distinct swelling. The length varies in all between 0-15 and 0-238 """; in the single specimens the variation is only slight. The thickness is about o -002— 0*004 mm. b. Microsclera; these are chelae arcuatae; they are rather small, the}' have an evenly, generally somewhat strongly curved shaft, but with regard to this curvature there ma}- be some little variation; the tooth is lancet-like, and the alse of the same length as the tooth. The teeth have such a direction, that the}' lie in a straight line drawn from one end of the chela to the other. The length of the chelae is 0-021 — 0-025™'", anc^ tne diameter of the shaft 0-002 — 0-028""". The chelae occur in great numbers in the dermal membrane, sometimes somewhat scattered and sometimes quite close-lying; this difference is probably due to the greater or less contraction of the membrane. As I find no characters separating this species from H. baculifera Tops., I have referred it to the latter; especially the figures cited appear to me very like the spicules in the present species. Locality: Station 1, 620 30' Lat. N., 8C 21' Long. W., depth 132 fathoms; station 9, 640 18' Lat. N., 27° 00' Long. W. , depth 295 fathoms; station 54, 630 08' Lat. N., 1 50 40' Long. W. , depth 691 fathoms; station 86, 650 03' Lat. N., 230 47' Long. W., depth 76 fathoms; station 94, 640 56' Lat. N., 360 19' Long. W., depth 204 fathoms; station 98, 650 38' Lat. N., 26° 27' Long. W., depth 138 fathoms; further it has been taken at 63° 12' Lat. N., 200 06' Long. W., depth 270 fathoms (The fishery investigation steamer "Thor"), and East of the Faroe Islands, depths 220 and 250 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902); in all about 14 specimens. The station on which most specimens were collected was station 85, the sponge here growing on tubes of Placostegus. The enumerated localities are situated in the Denmark .Strait, South of Iceland and East of the Faroe Islands. Geogr. dis/r. Topsent records the species from the Mediterranean North of Algiers, and at 38° 35' 3°" Lat. N., 28° 05' 45" Long. W., depth about 660 fathoms. PORIFERA. III. 7, 24. H. levis n. sp. PI. VIII, Fig. 2. In crusting and very thin; surface finely hispid. Spicule/,: megasclera; flic skeletal spicules acanthostyli with a somewhat swollen head and small spines, o-o8—o-2^"n", not divided into hvo groups ; •¥ the dermal spicules polytylote tylota or subfylota o-i6—o-2i""" ; microsclera small chela arcuatw 0'02I — -O'OSj""". The specimens of this species grow on Brachiopods, shells of Astarte and other mussels and on Placostegus trideufatus. The greatest extent, to which the species reaches, is igmm; the sponge forms an exceedingly thin incrustation, the thickness is scarcely above o-iomm. The colour (in spirit) is light brownish yellow. The surface is finely and densely hispid from projecting skeletal spicules. The dermal membrane is a thin film. Oscula and pores were not observed. The skeleton. The dermal skeleton; the dermal spicules form bundles which go to the surface in an oblique, often very decumbent direction; these bundles are rather scattered. In the membrane the chelae are found sometimes rather numerously, at other times more scattered. The main skeleton consists in the ordinary way of acanthostyli with the head-ends on the substratum; the larger of them project beyond the surface, making this hispid. A small amount of spongin is found at the base. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli which have a somewhat characteristic shape; they are straight or generally somewhat curved; the head-end is somewhat swollen, and they taper into a long apex; as they are rather thick at the head-end and are not especially long, they become slightly club-shaped. The head-end has strong spines, in the small styli the other spines are also rather pronounced, but in the larger ones the spines 011 the shaft are small, the shaft thus almost being merely gritty; in the longer styli the spines are scattered towards the point, but there is generally no long, smooth apical part. The size varies much, but the styli are not divided into two groups. The length is o-o8— 0-25 mm, the styli thus being rather short; the diameter of the head is about 0014 — cvo3mm. 2. The dermal spicules are slender, straight tylota or subtylota which are distinctly polytylote; they have a generally rather distinct, lougish swelling at each end, the shaft is a little thinner in one end, and the swelling in this end is therefore more marked than in the other. The length is cvi6— 0-21 mm, and the diameter about 0-0028— 0-004 mm. D- Microsclera; these are chelse arcuatae; they are rather small, the shaft is somewhat strongly curved, the alae are nearly triangular and the tooth elliptical and of the same length as the alee. The length of the chela is 0-021 — o-024mm, and the diameter of the shaft about o-oo28mm. The chelse seem to be confined to the dermal membrane. This species stands very near to baculifera, but I consider it as distinct; it is especially the slightly spined acanthostyli which distingush it, and the dermal spicules are also more distinctly polytylote. Locality: Station 9, 640 18' Lat.N., 270 00' Long. W., depth 295 fathoms; station 25, 630 30' Lat. N., 54° 25' Long. W. , depth 582 fathoms; station 85, 630 21' Lat. N., 250 21' Long. W., depth 170 fathoms; station 89, 640 45' Lat. N., 270 20' Long. W., depth 310 fathoms; further it has been taken at 620 29' Lat. N., 50 17' Long. W., depth 160 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902). In all seven specimens. The localities are situated in the Davis Strait, the Denmark .Strait and East of the Faroe Islands. The Ingolf-Expedition. VI. 3. 10 _, PORIFERA. III. 74 25. H. bractea n. sp. PL, VIII, Fig. 3. Incrusting; surface hispid. Spicula: megasclera; the skeletal spicules acanthostyli, divided into two groups, large, with a small head, only spined in the lower part, 0-28— o-j6 """, small, without head, entirely spined. 0-12—0-15"""; the dermal spicules tylota 0-27—0-50"""; microsclera chelce arcuate 0-026' — 0-034""". Of this species we have only a very small specimen, and the description will therefore in some respects not be quite satisfactory. The specimen grows on a Brachiopod-shell together with a specimen of Hymenancora duplicata 11. g. et sp. (to be described hereafter), and a small specimen of Melonanchora emphysema. It forms a very small, almost circular incrustation, scarcely two millimeters in diameter and very thin; it bears about in the middle a low, cylindrical papilla. The colour (in spirit) is greyish, and the sponge is somewhat transparent. The surface is in the present state hispid from projecting skeletal styli. About the dermal membrane I can say nothing, and also nothing about pores and oscula ; probably the papilla mentioned is an osculum, but I could not observe it. The skeleton. The dermal skeleton seems to consist of scattered bundles of dermal spicules, and it is, so far as I could observe, relatively weakly developed. The main skeleton is constructed in the ordinary way and consists of vertical acanthostyli with their heads on the substratum, and it is somewhat dense; the longest of the acanthostyli project beyond the surface, and it seems to be so also in the undamaged sponge. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli which are divided into two groups, large and small. The large acanthostyli are straight, they have a small head-swelling and taper evenly into a long apex which is a little more abruptly pointed outermost; they are spined only on the basal part, at most on the half part; the spines are of medium size, largest below; they are placed most densely on the head-swelling, but more dispersed outwards. The small styli have no head-swelling; the base is the thickest part and from here they taper evenly to the point, thus as- suming a club-like shape; these styli are spined in their whole length, the spines at the base radiate straight out, those on the shaft are reclined. The length of the large styli is 0-28— 0-36 mm, and the diameter of the head is about o-02n,ra; the length of the small styli is 0-12— o-i5mm with a diameter at the base of ooi4mm. 2. The dermal spicules are straight and somewhat slender tylota, the end- swellings are distinct but not large; the length varies rather considerably, from 0-27 — 0'50mm, and the diameter of the shaft is 0-004 — o-oo7mm. b. Microsclera ; these are chelte arcuatse, they have a curved shaft, elliptical teeth and lobe-shaped but somewhat narrow alae. The length of the chela is 0-028 — 0-034 n,m, and the diameter of the shaft 0-004— 0-005 mm. The chelje seem to occur through the whole tissue, but are seen especially at the surface. Locality: Station 89, The Denmark Strait, 640 45' Lat. N., 270 20' Long. W., depth 310 fathoms. 26. H. laevistylus n. sp. PI. VIII, Fig. 4. Incrusting. Spicula: megasclera : the skeletal spicules acanthostyli with a very small head, only spined 011 and just at I In- head, for the rest smooth, very uniform in size. 0-44 — 0-48""" : the dermal spicules tylota varying to strongyla, o-2j — o-j4""" ; microsclera cliche arcuata- 0-045 — 0-052""". PORIFERA. III. 75 Of this species only one very small specimen is present, growing as an incrustation on the inside of a Pecten-shell] it is longish and has a greatest extent of only 3*5 ram. The colour (in spirit) is whitish. The dermal membrane is thin and densely filled with chelae. Oscula and pores were not observed. The skeleton. The dermal skeleton consists of bundles and spicules, which are scattered in different ways from near the base to the dermal membrane; it seems to be rather diffuse; there is no skeleton of dermal spicules lying horizontally in the dermal membrane, but this latter is densely filled with chelse. The main skeleton seems to be somewhat slightly developed, it consists of acanthostvli which are all of the same size, and have the heads based on the substratum. I could detect no spongin. Spicula: a. Megasclera. 1. The skeletal spicules are very slightly spined, almost smooth acanthostyli; they are straight or slightly curved and have a slightly inflated head; this latter bears more or fewer, but generally only few small spines; near the head the style may be very finely gritty, but for the rest it is quite smooth. The styli are only of one form and very slightly varying in size, so that small forms do not occur. The length is about 0-44 — 0-48 mra, and the thickness of the head is about 0*017 mm. 2* The dermal spicules are tylota, which are straight, slightly thickened in the middle and with small end-swellings; these latter may be very small or absent, the spicules thus becoming strougyla; the length is 0-27 — o*34ram and the thickness in the middle 0*005 — 0*007 mn*. b. Micro- sclera; these are chelse arcuatse; they have a rather curved shaft which is a little recurved at the outermost extremities, the alae are lobe-shaped and the tooth narrowly elliptical; the length of the chelse is 0*045— 0*052 mm, anc- the thickness of the somewhat flattened shaft is 0*005— 0*008 mm. The chelse occur in specially large numbers in the dermal membrane. This species is easily distinguished and stands somewhat apart on account of its almost smooth styli, which are all of nearly the same length. Remarks: It might be thought, that this species represented only a young stage of some other sponge (a Lissodendoryx\ but I do not think this possible. To be sure we have no investigations on the skeleton of the youngest fixed stages of the sponges which may come into consideration here, and it is therefore not known, what the first beginning of the skeleton is in species with a reticulate or dendritical skeleton, and it is not impossible, that the styli may at first be placed vertically. The structure of the present species seems so fully to conform with that of Hymedesmia, however, that I think it must be in reality & Hymedesmia; the styli with a somewhat distinct head, and especially the chelse being crowded in the dermal membrane are good characters of Hymedesmia. Loeality: Station 89, the Denmark Strait, 64" 45' Lat. N., 270 20' Long. W., depth 310 fathoms. 27. H. Bowerbanki n. sp. PI. Ill, Fig. 8 a, PI. VIII, Fig. 5. Incrusting, thin; surface smooth. Spicula: megasclera ; the skeletal spicules short, club-shaped, strongly and entirely spined acanthostyli oj One size Taf- *• F*g- 6- 1903. Hymedcsinia filifera, Thiele, Arch, fiir Naturgesch., Jahrg. 1903, I, 391, Taf. XXI, Fig. 25 a — c. Incrusting, but not thin; surface smooth, bearing a number of thin, cylindrical oscular and pore- papillm. The dermal membrane solid, with horizontal spicules. The skeleton formed of dermal spicules strongly developed, the main skeleton rather weak. Spicula: mcgasclcra; the skeletal spicules entirely spined acanthostyli with the basal end not or slightly thickened, n-ij—o-jj""", not divided into two PORIFERA. III. 8? groups; the dermal spicules strongyla with a slight, double curvature. 0-27— 0-45'""'; microsclera cliche arcuatce 0-030 — 0-033""". This species forms thinner or a little thicker incrustations on stones; the surface bears a number (in the specimens to hand some few to about a dozen) of long papilla;, which generally reach a length of 6mm or a little more; they are cylindrical, generally a little thickened towards the apex, and they may vary in thickness from quite thin and thread-like to a diameter of about 0-5 mm. The largest of our specimens has a greatest extent of 25mm; the specimen figured by Schmidt I. c. is 35™™ long. The colour (in spirit) is greyish or dirty yellowish. The surface is smooth without projecting spicules. The dermal membrane is a tough and solid, easily separable membrane which is provided with horizontal spicules. Oscula and pores: the mentioned appendages are by Thiele (1. c.) declared to be oscular papillae, and this is also the case with some of them, but the greater part are pore- papillae; the oscular papillae have a simple opening in the summit, while the pore-papillae have here a pore-sieve stretched over the opening. So far as I could see on my somewhat damaged material there is also some difference in the shape of the papillae, the oscular papillae being more conical and the pore-papillae cylindrical and somewhat widened towards the apex. The skeleton. The dermal skeleton; the skeleton formed by the dermal spicules is by far the largest part of the whole skeleton. The spicules form fibres which run in different directions quite from the base up to the dermal membrane; these fibres consist of many spicules and are generally rather thick, they may f. inst. reach to a diameter of 0-36 mm. In the skin the spicules lie horizontally and in more than one layer, thus forming a close skeleton; they lie in all directions, but however somewhat bundle-like; the bundles in the different layers generally cross each other. Finally the dermal spicules form the skeleton in the wall of the papillae; they lie here in the longitudinal direction, but the spicules in the different layers crossing each other under acute angles and rather regularly. The main skeleton is formed mainly in the ordinary way of acanthostyli with their heads on the sub- stratum ; they do not reach to the dermal membrane. Where the fibres of dermal spicules rise from the base, they are seen to have just their basal end formed by acanthostyli. Spongin is found at the base. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli; they are straight or very slightly curved; the basal end is not or only slightly thickened; they taper evenly into the apex, but the outermost point is not long. They are spined in the whole length, on the base the spines are large and radiating, giving thus to some degree the impression of a head-swelling; the spines on the shaft are reclined. The styles vary much in length, but there are no groups. The length is 0-13 — 0-27 mm and the diameter at the base 0-017— 0-028 mm. 2. The dermal spicules are strongyla; they are slightly fusiform and have nearly always a curious and characteristic double curvature, more rarely they are somewhat irregularly curved or nearly straight; the length is 0-27 — 0-45 mm, varying a little in different individuals, and the diameter in the middle is 0-007— o-oi2mra. b. Microsclera are chelae arcuatae; they have a regularly curved shaft, the end-parts are not large, the tooth is elliptical, the alae have generally the lower edge but slightly incised and are more or less triangularly lobe-shaped in side view. The length is 0-030— 0-035™™ an<^ tne thickness of the shaft about 0003 mm. The chelae are found rather richly in the tissue quite down to the base, they are often abundantlv present along 38 PORIFERA. III. the fibres; in the dermal membrane they are ranch less frequent, but in the papillae they are more frequent on the inside, and they are very numerous in the pore-sieves. The identification of this species leaves no doubt according to the description and figures by Thiele; e.g. his figure of the strongyle with the characteristic curvature is quite in agreement. Schmidt mentions "Spangen", and Thiele has also found some single sigmates, but he thinks, that they do not belong to the species; now it is curious enough that I also found sigmates, but quite singly, and I think too, that they do not belong to this species; they are very scarce, and as the species always envelops some incrusted material, it is easily understood, that foreign sigmates may occur in it. Locality: Station 2, 630 04' Lat. N., 90 22' Long. W., depth 262 fathoms; station 15, 66° 18' Lat. N., 25° 59' Long. W., depth 330 fathoms, (bottom temperature -f- 0° 75 C); station 25, 63° 30' Lat. N., 54° 25' Long. W., depth 582 fathoms; station 89, 64° 45' Lat. N., 27° 20' Long. W., depth 310 fathoms; further it has been taken at 62° 26' Lat. N., 40 49' Long. W., depth 220 fathoms, and 62° 29' Lat. N., 40 12' Long. W., depth 283 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902). The localities lie in the Davis Strait, the Denmark Strait and at the Faroe Islands. The species is certainly an inhabitant of the warm area; to be sure station 15 has a negative bottom temperature, but this station is situated at the very border between the cold and the warm areas. Geogr. distr. The species was hitherto only known from Norway, South-west of Bukenfjord, depth 106 fathoms (Schmidt 1. a). 35. H. grandis u. sp. PL III, Figs. 13-14, PI. IX, Fig. 3. Incrusting, but of massive appearance; surface smooth, bearing a number of thin, cylindrical oscular and pore-papilla^. The dermal membrane solid, zvith horizontal spicules. The skeleton formed of dermal spicules strongly developed, the main skeleton zocak, chiefly consisting of bundles of spictdes, forming the lowermost part of the fibres of dermal spicules. Spicula : megasclera ; the skeletal spicules acanthostyli zvith a very slight or no head, spined almost in the whole length, 0-41 — o-js""" (not divided into two groups?) ; the dermal spicules long strongyla 0-48 — o-8omm ; microsclera tzuo forms, cliehr arcuat(F 0-042 — o'048'"m, sigmata o-oji — o-op6""". The specimens to hand of this species all grow on aggregated, large sponge-spicules; these spicules are then overgrown, enveloped or more or less imbedded by the sponge; although the species must thus in realit}' certainly be considered as incrustiug, it has however an outer appearance of being more or less massive; the upper part of the sponge has at the same time a somewhat bladder- like consistency which also contributes to its massive outer appearance. The surface bears a geuerally great number of long, thin papillae or appendages which may reach to a length of i2mm with a dia- meter of o-5 — i*5mm. The appendages may be more or less erect or decumbent, and they are generally more or less curved. The whole sponge is generally folded and wrinkled in different ways. The species may reach a considerable size, the largest specimen is about 50 mm long and has an apparent height of 15'""'. The colour (in spirit) is dirty yellowish or greyish white. The surface is smooth without projecting spicules. The dermal membrane is solid and easily separable, and it is provided PORIFERA. III. 89 with horizontal spicules. Osmla and pores: the mentioned papillse are oscular and pore-papillae; in outer appearance there is almost no difference between the two kinds, only the oscular papilla? are generally more conically pointed at the apex, while the pore-papillae are more broad here; the latter are closed by a pore-sieve, while the oscular papillse have a simple opening in the summit. The pore- papillae are more numerous than the oscular papillae. The skeleton. The dermal skeleton ; the skeleton consisting of the dermal spicules forms the greatest part of the whole skeleton; it consists of fibres and bundles which stretch in an irregular way from or nearly from the substratum up to the dermal membrane; the course of the fibres is, as said, irregular, and they are often more or less curved, and may thus be seen running somewhat parallel with the surface; the fibres may be of very different strength, but often rather thick, up to 0-3 ram, and consisting of many spicules. In the dermal membrane the spicules lie horizontally, but irregularly, crossing each other in all directions; they lie somewhat scattered, and the membrane is to be seen everywhere between them; they lie thus much more scattered than in filifera, and not bundle- like collected. The skeleton of the papillae is constructed quite as in filifera , and also here the spicules cross each other regularly and under acute angles. The main skeleton is quite irregular and scattered on account of the way in which the sponge grows 011 the substratum; it forms thick bundles scattered everywhere between the foreign sponge-spicules and other particles of the substratum, and always forming the lowermost part of a fibre of dermal spicules; the acanthostyli are thus not at all evenly distributed at the base of the sponge, but very scattered and only present as bundles, from which fibres of dermal spicules proceed. The bundles are generally large and consist of many spicules, they may have a thickness of 0-5 mm. At the base of the bundles there is a distinct mass of spongin. Spicula: a. Megasclera. 1. The skeletal spicules are long and slender acanthostyli; they are straight or nearly so and evenly tapering, but the outermost point is short; they have no or only a very slight head-swelling and are somewhat densely spined at the base and some way out, but on the largest part of the shaft the spines are somewhat scattered; at the base and especially a little above it the spines are somewhat large, but for the rest they are small. The styli do not generally vary much in length, from 0-41 — 075 nlm with a diameter at the base of 0-021 — 0-026 n,m; it will be seen that there is thus no very great difference in size between the styli; some smaller ones may however be found, reaching only o-i8mm in length, but these are very scarce and perhaps not always present. 2. The dermal spicules are long strongyla; they are straight, sometimes slightly, irregularly curved, and they may be slightly polytylote; the ends may be very slightly swollen. The length is 048— o-8on,ra, and the diameter in the middle 0-007 — 0-013 mm. Microsclera ; these are of two forms, chelae arcuatae and sigmata. 1. The chelae have a curved shaft, the free middle part of which is about one third of the length of the chela, the alae are lobe-shaped, the tooth elliptical, pointed. The length is 0-042— 0-048 mm, and the diameter of the shaft 0-005— 0-007 mm. 2- Tne sigmata are of common shape, more or less contorted up to a quarter of a turn; they vary considerably in size, the length is 0-031 — 0-096 mm and the thickness relatively 0-002— o-oo6mm; the larger forms are the most common. The two forms of microsclera occur at definite places in the sponge; in the dermal membrane both chelae and sigmata are present in equal numbers; the chelae occur moreover in the wall of the papillae, The [ngolf-Expedition. VI. 3. I2 qQ PORIFERA. III. especially outwards, and in rather great numbers in the membrane forming the pore-sieves, and in these places no sigmata occur; on the other hand, the chelae do not occur in the inner body, while the sigmata are present here in enormous numbers, filling the tissue and also occurring everywhere in the basal parts among the particles of the substratum. The consequence of this distribution of the microscleres is that the sigmata are far more numerous than the chelae. Embryos. In one of the specimens, which was cut through, some embryos were found; they reached to a diameter of 0-65 n,m; they smallest of them had no spicules, but the larger were richly provided with microselera, both chelae and sigmata; both forms were smaller than in the grown sponge, the chelae 0-031 mm and the sigmata not surpassing 0-040 mm; also in the embryo the sigmata were far more numerous than the chelae. No megascleres were present. Locality: Station 78, 6o°37'Lat. N., 27°52'Long.W., depth 799 fathoms; station 84, 620 58' Lat. N., 25° 24' Long. W., depth 633 fathoms; station 90, 640 45' Lat. N., 29° 06' Long. W., depth 568 fathoms. In all five specimens. The localities lie in the Denmark* Strait and on the eastern slope of the Reykja- naes Ridge. 36. H. digitata n. sp. PL III, Fig. 15, PI. IX, Fig. 4. Incrusting or of somewhat massive appearance; surface smooth, bearing some thin oscular and pore-papillce ; the dermal membrane with Iwrizontal spicules. Spicula: megasclera; the skeletal spicules acanthostyli, divided into two groups, large, without a distinct head and not entirely spined, 0-23 — 0-31""". small, with a distinct head and entirely spined, ow/ — 0-14""" ; the dermal spicules tylota 0-26— 0-417""" : microselera two forms, chela arena fa1 0-034 — 0-038""", sigmata 0-028— 0-030""". This species resembles the preceding in outer appearance, but the specimens present are small ; we have only two specimens, growing on stones together with other species of Hymedesmia and some other incrusting sponges. The sponge forms a basal, incrusting or more massive part, from which a number of long, thin papillae issue; in the present specimens the number of papillae does not exceed three; the)- are of the common shape and reach to a length of 7mm. As said the specimens are small, the basal part has a greatest extent of about 5mm. The colour (in spirit) is yellowish or whitish. The surface is smooth, and the dermal membrane constructed as in the preceding species. Oscula and pores are connected with the papilla? quite as in the preceding species. The skeleton. The dermal skeleton; the skeleton formed of the dermal spicules consists of more or less distinct fibres going from the basal skeleton towards the dermal membrane; in the membrane the spicules lie horizontally, and they are as usual lying close in the wall of the papilla; in the longitudinal direction, intercrossing at acute angles. The main skeleton consists of basal acantho- styli with their heads on the substratum. Spongin is present, but only to a very slight degree. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli; they are divided into two rather distinct groups, large and small; the large styli are slightly curved, they are thickest at the base but without any real head-swelling; they taper evenly but the outermost point is short, and they are spined in somewhat more than the basal half; the spines are small, only at the base a little larger. The small styli are straight and have a distinct head, the shaft is beset with relatively large PORIFERA. III. 91 spines in the whole length, the spines are directed downwards; on the head there are rather long, radiating spines. The length of the large styli is 0-25— 0-31 mm, and the diameter at the base o-02in,m; the small styli are o-n— o-i4ram long with a diameter of the head of o-02imm. 2. The dermal spicules are tylota which are cylindrical and straight or slightly, irregularly curved; the end-swellings are not large but distinct; the length is 0-26— o-4i7mm and the diameter in the middle 0-005— 0-008 mm. b. Micro- sclera are of two forms, chelae arcuatae and sigmata. 1. The chelae have an evenly curved shaft, the free middle part of which is a little more than the third part of the length; the alas are lobe-shaped and the tooth elliptical, rounded at the end. The length is 0-034 — 0-038 mra and the diameter of the shaft 0-005 ram. 2- The sigmata are of ordinary shape, more or less contorted up to a quarter of a turn. The length is 0-028— 0-050 n,m and the thickness between 0-002 and 0-003 mm. The chelae and sigmata seem to be present in about equal numbers; the chelae occur in the wall of the papillae, and for the rest both forms of microscleres seem to occur, so far as I could ascertain, through the whole body. This species is distinguished from the preceding in regard to the spicules by the smaller acantho- styli, the tylote dermal spicules and the much smaller sigmata; also the chelae are slightly different. Locality: Station 89, the Denmark Strait, 640 45' Lat. N., 270 20' Long. W., depth 310 fathoms. Two specimens. 37. H. trichoma n. sp. PL III, Fig. 16, PI. IX, Fig. 5. Incrusting ; surface smooth, bearing thin papillm. The iter mat membrane with horizontal spicules. Spicula: megasclera ; the skeletal spicules acanthostyli with a small head, spined in the 'whole length, they are divided into two groups, large, 0-20 — 0-24""", small, o-n — o-ij"""; the dermal spicules tylota 0-29 — o-j8"""; microsclera two forms, chclce arcuataz 0-034 — 0-042""", plane sigmata 0-058 — o-oj$""". Of this species we have only one specimen growing on a shell of an Asfarte; it forms a thin incrustation of a greatest extent of only 6mm, and it bears one long and thin papilla. The colour (in spirit) is light brownish. The surface is smooth. The dermal membrane is thin and not easily separated. About oscula and pores I can say nothing, as said, only one papilla is present. The skeleton. The dermal skeleton; the skeleton formed of the dermal spicules consists of bundles stretching from near the base to the dermal membrane; in the membrane there are horizontal spicules, but they are scattered and not at all dense-lying. The main skeleton is arranged quite in the ordinary way, consisting of erect acanthostyli with their head on the substratum and evenly distributed over it; the largest of them reach to the surface. A small amount of spongin seems to be present. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli which are straight or nearly so, the head-swelling is small, and they taper slightly towards the point, which is short; they are rather densely spined in the whole length, but the spines are small, only longer at the base; though they do not vary much in length they are yet divided into two distinct groups; the length of the large styli is 020— 0-24 mm, and of the small o-n— o-i3"'m; the diameter of the head is about o-02imm, and it is nearly the same in the large and the small styli on account of the basal spines being larger g2 PORIFERA. III. in the small than in the large styli. 2. The dermal spicules are tylota, they are straight or generally slightly and somewhat irregularly curved, often with a curvature recalling to some degree that found in the dermal spicules of H.filifera; the end-swellings are small, sometimes almost dis- appearing; the length is 029— 0-38""" and the diameter 0-004— 0-007 mm. D- Microsclera are of two forms, chelae arcuatse and sigmata. 1. The chelae have a curved shaft the free middle part of which is more than one third of the length, the alae are lobe-shaped, their lower margin not much incised; the tooth is narrowly elliptical; the length is 0034 — 0*042 mm and the diameter of the shaft about 0-003 """• 2. The sigmata are of common shape, but they are quite or nearly quite plane; the length is not very variable 0-58—075'"'", generally nearest the latter size; they are relatively thin, the thickness being 0.0028""". As far as I have been able to ascertain, both chelae and sigmata occur through the tissue, while in the dermal membrane only the chelae occur, but here in great numbers, and in places King densely. Of the microsclera the chelae are the most numerous. This species is distinguished from grandis and digitata by its plane, thin sigmata and besides by characters in the other spicules. Locality: Station 85, the Denmark Strait, 630 21' Lat. N., 250 21' Long. W., depth 170 fathoms. One specimen. 38. H. macrosigma 11. sp. PL IX, Fig. 6. In crusting; surface smooth. Spicula : megasclera ; the skeletal spicules acanthostyli with a small head-swelling, spined in the whole length, but the spines much dispersed outwards, o-ij — 0-28""", not divided into two groups ; the dermal spicules strongyla or subtylota 0-23—0-28"""; microsclera three forms, chela- arcuatce 0-020— 0-032""". sigmata of two forms, large 0-18 — 0-208, small 0-06— 0-089""". We have three specimens of this species, one of them grows on aggregated sponge-spicules; it incrusts these all round, so that they are chiefly situated in the interior of the sponge, but stretching out here and there. Of the other two specimens one grows on a Brachiopod-shell, the other on a basalt block. The specimens are rather small, one only about 8mm, the others 12'"'" in greatest extent. The colour (in spirit) is yellowish white or yellow. The surface is smooth without projecting spicules. The dermal membrane is thin, it is densely charged with chelse and sigmata; some small, circular openings could be observed in it. The skeleton is highly irregular and confused in the first examined specimen, viz. that im- bedding sponge-spicules, on account of the manner in which the sponge envelops the substratum. The dermal skeleton is represented by dermal spicules which are found scattered through the whole sponge; in single places they may form a bundle stretching towards the surface; in the dermal mem- brane they are not seen, or at all events only some few, while, as said, the membrane is filled with microscleres. In one place the dermal spicules were lying parallel and forming something like a conical projection - - perhaps an oscular cone — but the state of the specimen did not allow this to be decided. The main skeleton is still less developed, and the acanthostyli are only present in small numbers; they are seen here and there with the head based on the substratum but otherwise quite confused and pointing in all directions. While the skeleton is thus on the whole little developed, the sponge is on PORIFERA. III. 93 the other hand densely filled with microscleres. When a vertical section is examined, the view is therefore somewhat curious; in the interior foreign sponge-spieules are seen, and for the rest the microscleres are predominant, filling the other space, the dermal spicules being only seen scattered between the other elements, and it is only by close examination that an acanthostyle can be observed here and there. The condition of the skeleton is, as seen below, due to the way in which the sponge grows, and the principle of the construction is evidently the same as in the other species of Hyme- desmia. There seems to be a little spongin at the base of the acanthostyli. — On examining the other specimens, which only came into my hands later, it proved, that the skeleton was here of the ordinary construction and the sty li were as usually placed on the substratum; otherwise it agreed with the above description, the other space being occupied by dermal spicules and densely charged with micro- scleres. Here also the styli of the skeleton were somewhat scarce and arranged very dispersedly. — It is of some importance to notice the facts with regard to these different specimens, as we see it clearly proved here, that specimens of Hymedesmia may, when growing on loose material, assume a shape and a manner of growth which may give rise to mistakes by influencing the arrangement of the skeleton, though the construction of this latter is principally the same as in species of Hyme- desmia growing on a flat and firm substratum. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli; thev are straight and the head-swelling is small or wanting; the spines on the basal part are somewhat large and close-standing, on the rest they are small, reclined and few in number; the smallest styli are somewhat more spiued. The length is 0-13— o-28ram and the diameter at the head about o-020mm. 2. The dermal spicules are straight, cvlindrical strongyla or subtylota; the ends are generally swollen, but only to a very slight degree. The length is 0-23— o-38mm and the diameter is 0-0057— 0-007 """. b. Microsclera are three forms, chela? arcuatse and sigmata of two sizes. 1. The chelae are of the common shape, the shaft is curved, the tooth elliptical and the alse lobe-shaped; they vary somewhat in size, the length is 0-020— 0-032 mm amj the diameter of the shaft 0-0015— 0-0028 mm. 2. The large sigmata are of ordinary form, but somewhat elongated and generally only slightly contorted; they are of a considerable and very uniform size, the length is 0-18— 0-208 mm and the thickness o-oio-o-onmm. 3. The small sigmata are of a less regular shape and they are contorted, generally a quarter of a turn or nearly so; their length is 0-06— 0-089 n,m auc^ ^ie thickness 0003 m'". As said the microscleres occur in great numbers all through the tissue; in the dermal membrane all three forms occur, but the chelae are here present in greatest number and very close-lying. This species shows, in one specimen, a manner of growth quite as is found in grandis, and it also shows resemblances to this species otherwise, but it is easily distinguished from it and from the related species by the presence of two forms of sigmata. As seen from the description I have not been able to decide whether the species in a more perfect state may be provided with papilla;. Locality: Station 54, 63° 08' Lat. N., 150 40' Long. W., depth 691 fathoms; station 78, 6o° 37' Lat. N., 270 52' Long. W., depth 799 fathoms; station 89, 640 45' Lat. N., 27°2o' Long.W., depth 310 fathoms. The localities lie in the Denmark Strait and South of Iceland. g. rORIFERA. III. 39. H. pugio n. sp. PL IX, Fig. 7. fuc nesting; surface somewhat liispid. Spicula : megasclera; the skeletal spicules acanthostyli with a distinct head, only spined on the lower part, they are divided into two groups, large o-j8 — 0-54""", small 0-12— o-2o""" ; the dermal spicules thin styli 0-27 — o-ji"""; microsclera two forms, chela arcualm o-02i — 0-040""", sigmata, small and curved in a somewhat circular way, plane or nearly plane, 0-014 — 0-OIJ'""1. Of this species we have one specimen, growing on a stone; it forms a thin incrustation of a greatest extent of about 20mm, and the thickness does not exceed 0'5rnm. The colour (in spirit) is white. The surface is somewhat hispid from the projecting acanthostyli. The dermal membrane is thin and not separable, sparingly provided with dermal spicules, but somewhat more richly with chelae. A number of circular openings of canals are seen shining through the membrane. The skeleton. The dermal skeleton is not much developed; it consists of dermal spicules which are, so far as I could ascertain, lying partly more or less horizontal in the membrane, but for the greatest part projecting. The main skeleton consists of acanthostyli with the heads placed on the substratum; it is rather dense with the spicules close-standing; the longest of the styli project through the dermal membrane. The heads of the styli are at the base inserted in a somewhat slight mass of spongin. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli which are straight or only very slightly curved and taper evenly into a long apex; the head is round and not large but distinct. They are spined at the base and some way out, but the larger apical part is smooth; the spines are small. With regard to size the styli are divided into two groups, but otherwise they are quite similar. The large styli have a length of 0-38 — 0-54 mn1 with a diameter at the head of 0-021 — 0-028™"'; the small styli are 0-12— o-20mm long and the head 0-015 — o-02imm thick. The small styli are the most numerous. 2. The dermal spicules are rather thin styli which are cylindrical, straight or slightly curved and taper into a long and fine point. The length is 0-27 — 0-31 mm with a diameter of about 0-003 mm. b. Microsclera are of two forms, chelae arcuatse and sigmata. 1. The chelae have a sometimes rather strongly curved shaft and relatively small end-parts; the alga are lobe-shaped but somewhat narrow, the tooth is elliptical. The size of the chelae is somewhat variable, the length being 0-02 1—0-040''"'' and the thickness of the shaft 0-004— 0-006 n"n. 2- The sigmata are very small and fine and they are somewhat circularly curved, so that the length is not much greater than the breadth; they are plane or almost plane; the length is 0-014— o-oi7mm an(i tne thickness o-ooi""1' or still finer. Both forms of microsclera are seen especially in or near the dermal membrane. Embryos. The specimen contained a great number of embryos; they are globular or lentiform and they were easily seen in the thin sponge on account of their white colour. They have an average diameter of o-35"'m. They contained either no spicules or also developmental forms of the chelae but no megascleres. Locality: Station 15, the Denmark Strait, 66° 18' Lat. N., 250 59' Long. W., depth 330 fathoms (bottom temperature -f- o° 75 C). Only one specimen. PORIFERA. III. 95 40. H. consanguinea n. sp. PL IX, Fig. 8. Incrusting; surface finely hispid. Spicula: megasclera; the skeletal spicules acanthostyli with a small or no head-swelling, they are divided into two groups, large, zuith a smooth apical part, 0-21 — 0-29™'", small, entirely spined, cno — o-ij"""; the dermal spicules tornota, 0-15—0-10""" ; microsclera two forms, chelcr arcuata: 0-028 — 0-057""", contorted sigmata 0-014 — o-oij""". This species grows as thiu incrustations on living Brachiopods and one on a Retepora: the sponge covers generally the whole shell and may thus reach a greatest extent of 16 mm; it is exceed- ingly thin, not reaching 0-5 n,m in thickness. The colour (in spirit) is whitish. The surface is short and finely hispid. The dermal membrane is very thin and hardly observable. The skeleton. The dermal skeleton is not much developed and somewhat diffuse; it consists of small bundles formed by a few spicules; the bundles stretch from the skeleton below up to the dermal membrane. The main skeleton is constructed in the ordinary way and consists of acanthostyli with the heads based on the substratum; the styli are not densely placed. The longer styli stretch beyond the dermal membrane, thus giving rise to the hispidity of the surface. So far as I could observe there is a very small amount of spongin at the base of the skeleton. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli which are divided into two well separated groups, large and small. The large styli are straight or generally slightly curved near the base; they are thickest at the base but have no or only a small head-swelling; they taper evenly from the base, but the apex itself is not long-pointed ; the styli are somewhat densely spined in almost the lower two thirds, the spines being less dense outwards; at the base the spines are somewhat large and blunt, for the rest they are small. The small styli have a similar shape as the large, but they are spined in the whole length. The large styli have a length of o-2i — 0-29 mm and a diameter at the base of croi8— 0-025 """• The small styli are o-io — o-i3mm long with a diameter at the base of about 0-014""". 2. The dermal spicules are tornota which are somewhat thin, straight and cylindrical; the ends have short points; they are not of a simple tornote shape in so far as one end has a generally slight swelling; sometimes also the other end may show an indication of a swelling. The length of the tornota is 0-15 — 0-19 mm and the diameter about 0-0025""". b. Microsclera are of two forms, chela; arcuatae and sigmata. 1. The chelse have a slightly curved shaft and relatively small end-parts, the alae are lobe-shaped and the tooth elliptical. The length of the chela is 0-028— 0-057 mm and the diameter of the shaft 0-003— o-oo6mm. 2- The sigmata are thin and contorted, generally a quarter of a turn; their length is 0-014 — 0-017 and the thickness o-ooo8mm. The microscleres are seen through the whole tissue of the sponge. This species shows some resemblance to H. (Hymeraphia) ?nucronata Tops, with regard to the different categories of spicides, but the size of these is different for all forms and especially for the tornota, and there is only one form of chelse in the present species. The species is easily distinguished from the preceding by the sigmata and the tornote dermal spicules. Locality: Station 25, 63° 30' Lat. N., 540 25' Long. W., depth 582 fathoms, and at 700 32' Lat N., 8° 10' Long. W., depth 470 fathoms (The Ryder Expedition 1891 — 92). In all five specimens. The localities lie in the Davis Strait and the Denmark Strait. 96 PORIFERA. III. 41. H. planca n. sp. PI. X, Fig. 1. Incrusting; surface densely hispid. Spicnla: megasclcra ; the skeletal spicules acanthostyli with- out a distinct head, divided into two groups, large, only spined at the base, o-jj—o-6j""", small, spined about in the lower half, 0-16—0-27"""; the dermal spicules tylotornota osi — 0-29'"'"; microsclera three forms, chela' arcuatce o-oiS—o-o^1/""", sigmata of hvo forms, large, contorted, 0-021 — 0-028""", small, plane, somewhat circularly curved, 0-014""". This species forms incrustations on Brachiopods, shells, Bryozoa and small stones; it reaches a greatest extent of about i5mm, with a thickness of about o-5mra. The colour (in spirit) is white in all specimens. The surface is distinctly and densely hispid. The dermal membrane is very thin and transparent; it is perforated by a multitude of close-lying circular openings of different sizes, which are oscula and pores, but there is no such difference in size between them, that it can be decided therefrom which of them are incurrent and which excurrent openings; the openings are seen only when the sponge is somewhat dried; when lying in spirit close-standing openings of canals are seen to shine through the membrane. The skeleton. The dermal skeleton consists of bundles of dermal spicules, which stretch obliquely from the lower part of the main skeleton up to the dermal membrane; the bundles are small, each not consisting of many spicules; the spicules all have the rounded ends inwards and the points outwards; the spicules in the bundles are a little divergent outwards and bear the dermal membrane, but they do not penetrate through it or only very slightly; as the longest skeletal styli reach the dermal membrane and project through it, the bundles of dermal spicules are thus lying between the ends of the long skeletal styli. The main skeleton is constructed in the ordinary way of vertical acanthostyli with the heads based on the substratum; it is somewhat dense, and the longer spicules reach as said to the dermal membrane and project beyond it. At the base of the skeleton there is a distinctly visible sponginous substance. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli; they are divided into two distinct groups, large and small; the large styli are more or less curved near the base, this latter is the thickest part of the style but there is no distinct head; they taper evenly into a long apex which is a little more abruptly pointed outermost. They are only spined on a short basal part and the spines are somewhat large. The small acanthostyli are straight and relatively more spined than the large, the spines are continued to or near to the middle; the spines are also relatively more robust than in the large styli. The length of the large styli is 0-35 — 0-65 mm with a diameter at the base of 0-021 — 0-028 n,m, and of the small 0-16— o-27ram with a basal diameter of 0-017— 0-022 mm. 2- The dermal spicules may be termed tylotornota; they are cylindrical and straight, one end is more or less thickened or has an oblong swelling which goes however evenly over into the shaft, the other end has a shorter or longer sharp point. The length is 0-21— o-29mm and the diameter in the middle 0-003 mm. b. Microsclera are of three forms, chelae arcuatse and sigmata of two forms. 1. The chelae have a somewhat strongly curved shaft, the end-parts are relatively short, the alae are lobe-shaped and the tooth elliptical. The length is very variable, from 0-018 to 0-057""", but the shape remains the same. PORIFERA. III. 97 The shaft is not cylindrical but somewhat flattened and therefore of different thickness in side and front view, the thickness is in relation to this and to the size of the chela 0-003 and o-oo6mra to 0-007 and 001 1 mm; the larger chela? are the most numerous. Sometimes the chelae have the shaft less strongly curved. 2. The sigmata of the larger form are somewhat irregularly curved and they are contorted, always a quarter of a turn or nearly so; their length is rather constant, about 0021 — o-028mm and the thickness about o-ooimm. 3. The small sigmata quite resemble the sigmata in II. pugio; they are likewise strongly curved, and they are plane; their length is about o-oi4mm and the thickness scarcely goes beyond o-ooo8mm. The microsclera occur through the whole tissue and the chelae are seen in great numbers in the dermal membrane. Locality: Station 15, 66° 18' Lat. N., 250 59' Long. W., depth 330 fathoms (bottom temperature 4- o° 75 C); station 25, 630 30' Lat. N., 540 25' Long. W., depth 582 fathoms, and East of the Faroe Islands, depth 230 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902). The localities are situated in the Davis Strait, the Denmark Strait and East of the Faroe Islands. The species must be an in- habitant of the warm area; it is true that station 15 shows a negative bottom temperature, but this station lies just at the very border between the cold and the warm areas. The three species just described must be somewhat nearly related, but besides by other characters they may be distinguished by their sigmata alone; H. pugio has only small, plane, circularly curved sigmata, consan guinea only contorted sigmata and planca two forms, contorted and plane. 42. H. cultrisigma u. sp. PL X, Fig. 2. In eras ting ; surface hispid. Spicula: mega sclera; tJie skeletal spicules acantJwstyli with a very slight or no head, they arc divided into two groups, large, only spined below, o-j6 — o-8o""", small, spincd in the basal half, 0-21 — o-jo"""; the dermal spicules tylota 0-25 — 0-32""" ; microsclera three forms, chelce arcuatce 0-026 — 0-042""", sigmata of hvo forms, large, peculiar, somewhat baud-shaped, 0-028 — 0-035' small, plane, 0-014 — 0-020' 'is 1 mm This species grows as very thin incrustations on different bottom material as pebbles and shell-fragments and in one case on a Hexactinellid skeleton. The greatest extent it reaches is i6ram; it may vary a little in thickness, but it is however always very thin, not reaching 0-5 mm. The colour (in spirit) is whitish. The surface is in the present condition of the sponge very hispid with long projecting spicules. The dermal membrane is a thin film. Oscula and pores were not seen, but some circular canals could be seen through the dermal membrane. The skeleton. The dermal skeleton is formed by bundles of dermal spicules stretching from or almost from the base to the surface; the bundles have a more or less oblique direction and are often almost horizontal for a distance; they do not project beyond the surface, and there are no spicules lying in the membrane itself. The bundles are generally weak, consisting of only few spicules. The main skeleton has quite the ordinary construction and consists of acanthostyli with the heads placed on the substratum; the long styli project beyond the surface. At the base there is a small amount of spongin. The Ingolf-Expcdition. VI. 3. 13 98 PORIFERA. III. Spicula: a. Megasclcra. i. The skeletal spicules are acanthostyli which are divided into two sizes, large and small; the large styli are slightly curved near the head which is only slightly thickened, while the other end forms a long-pointed apex; the head and a short space above it are spined, while the whole of the rest of the shaft and apex is smooth. The small acanthostyli are generally straight and with the head still less thickened; they are more spined than the large, the spines covering the basal half part or more, and the spines are relatively larger. The length of the large styli is 0-56— o'8omm and the diameter of the head about 0'028mm, of the small styli o-2i — o-30mm with a diameter of cro2i — 0-025 mm. 2. The dermal spicules are tylota; they are straight and the shaft is slender, the end- swellings are distinct, but the}' are not formed abruptly but pass gradually into the shaft. The length is 0-25 — 032 mm and the diameter of the shaft is 0-003 mm. Some few developmental forms were found, the thinnest of them being monactinal. b. Microsclcra are of three forms, chelse arcuatse and sigmata of two forms and sizes, large, peculiar, and small. 1. The chelse are of ordinary shape, the shaft is evenly curved and the end-parts are relatively small; the tooth is elliptical and the alse lobe- shaped; the shaft is flattened, elliptical in section. The chelse vary somewhat in size, the length is 0-026— 0-042 mm and the thickness of the shaft 0-004— o,oiomm; with regard to the latter measurement it must be remembered, that the shaft is about twice as thick when seen in front as when seen in side view. The intermediate sizes of the chelse are scarce and hence they could be said to be present in two groups of sizes. 2. The large peculiar sigmata are of a curious shape; they may be de- scribed as having the curved end-parts somewhat long and terminating in a hook; they are contorted generally a quarter of a turn, and the hooks are again bent a little out of the plane; but the most interesting feature is that the rod forming the sigma is not cylindrical but compressed and thus somewhat band-shaped. The size of the sigma from one curve to the other is 0-028 — 0-035 mm, an<^ the thickness is 0001 and 0-003""" for the small and the large diameter respectively. 3. The small sigmata are of ordinary shape and they are plane; the length is 0-014 — 0-020 mm and the thickness about o-ooimm. The chelse are present especially in the dermal membrane and rather numerous; the two forms of sigmata are seen through the whole bod}'. Locality: Station 78, 6o°37' Lat. N., 27°52'L,ong. W., depth 799 fathoms; station 81, 61° 44' L,at. N., 2 70 00' Long. W., depth 485 fathoms. In all three specimens. The localities are situated on the Reykja- nses Ridge South-west of Iceland. 43. H. mucronata Tops. PL X, Fig. 3. 1904. Hymcrapliia mucronata Topsent, Resultats des camp, scient. du Prince de Monaco, Fasc. XXV, 165, PL XIV, fig. 4a-d. Incrttsting ; surface hispid. Spicula: megasclcra; the skeletal spicules acanthostyli zaith no distinct head, the larger spined at the base, the small entirely spined, 0-12 — 0-65""", not divided into tzvo groups; the dermal spicules fusiform oxytornota 0-22— 0-268""" ; microsclera three forms, chela of tzvo forms, ordinary 0-021— 0-025""", fee 11 liar, with some processes at each end. 0-021 — 0-026""", sigmata, large and fine, 0-028 — 0-051""". PORIFERA. III. 99 Of this interesting species we have one specimen growing as a small incrustation on an Ony- chocella; its greatest extent is 8mm, and it scarcely reaches o-5mm in thickness. The colour (in spirit) is greyish. The surface is hispid on account of the projecting skeletal styli. The dermal membrane is a thin film, it shows a multitude of larger and smaller circular openings representing I think both oscida and pores. The skeleton. The dermal skeleton consists of single dermal spicules or of small bundles of these, stretching from the main skeleton to the surface in a more or less oblique direction. In the membrane itself there are no horizontal spicules. The main skeleton has the common construction, consisting of vertical acanthostyli with the heads placed on the substratum; the longest of the styli project beyond the surface, thus causing the hispidity of this; the skeleton is somewhat dense. At the base there is an amount of spongiu, which is only slight but forms however a continuous basal lamella. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli which are more or less, generally only slightly, curved; they are thickest at the base but have no distinct head, and they taper into a long apex. The larger styli are spiued at the base, but the spines are not large and outwards they become smaller and gritty, and they soon disappear; the small styli are generally straight, they are spined in the whole length, and the spines are relatively larger than in the long styli. The styli vary much in size, but there are no separated groups. The length is cri2 — o-65mm and the thickness at the base o-oi— cro24rora. 2. The dermal spicules are of a characteristic shape and may best be termed oxytornota; they are rather thick and much thickened about the middle, so that they are strongly fusiform; they taper towards each end, one end is tornote-shaped, or sometimes more rounded, and terminates in a little mucro, the other end is of an oxeote shape, tapering some- what evenly, but the outermost point is generally short; in some cases this latter end is so short pointed and has such a shape that the spicule might be termed a tornote. The spicules are often somewhat curved near the short pointed end. The length is o-22 — o-268mm, and the diameter in the middle is o-oo8 — 0'0i7mm. b. Microsclera are of three forms, chelse of two forms and sigmata; the chelse are ordinary chelse arcuatse and peculiar chelae, i. The ordinary chelse arcuatse have an evenly curved shaft, the alae are somewhat claw-shaped triangular, the tooth elliptical; the length is cro2i — o-o25mm and the thickness of the shaft about 0'002mm. 2. The peculiar chelse are spicules, which are somewhat difficult to understand; they consist of a curved shaft the ends of which are a little dilated and from this dilatation a few processes are produced; the processes may be of different number and differently, often quite irregularly arranged, but generally there are two larger processes at the end of the dilated part, and behind these two others, generally smaller processes; it is probable that the two larger processes answer to a cleft tooth, and the other small processes to alee, but this it is for the present not possible to decide with certainty; on the other hand I consider it as certain, that the spicule is a chela and not a sigma. In spite of the number of processes at each end I think however, that it cannot at all be considered as an ancora; the whole shape of the dilated end-parts seems to me to point towards a chela. The length of this spicule is o-02i— o-026mm and the thickness of the shaft is about o-oo28mm. 3. The sigmata are of a very characteristic shape, they are rather large but exceedingly fine, generally they are strongly curved in the middle and the arms have a hook-formed bend at the end; sometimes they are more evenly curved; they are more or less contorted. 13* IOO PORIFERA. III. They vary somewhat in size, the length from one hook to the other is 0-028— 0-051 mm and the thickness about o-ooiomro. The mieroselera are especially found in the dermal membrane, the ordinary chelae and the sigmata are however also seen throughout the tissue. As I have seen a preparation of the type-specimen, kindly sent to me from Professor Top- sent, the determination is certain; as will be seen the shape and measurements of the spicules agree very well, only the dermal spicules are different, but I think that Topsent's figure and measure- ments are taken from non-typical spicules; the few dermal spicules present in the preparation sent to me quite agreed with my figure (PI. X, fig. 3 b) and were measured to o-26mm in length with a diameter of 0-017 mm. Locality: Station 25, the Davis Strait 630 30' Lat. N., 54° 25' Long. W., depth 582 fathoms. One specimen. Geogr. distr. Topsent (I.e.) has the species from 37°55'Lat.N., 25°24'Long.W., depth 465 fathoms. 44. H. tenuisigma n. sp. PL X, Fig. 4. Incrusting ; surface smooth. Spicula: megasclera; the skeletal spicules acanthostyli with a- round head, divided info hvo groups, large, only spined below, o-jo — o-8j""". small, entirely spined, o-iiq — o-i6""" ; the dermal spicules long strongyla o-j2 — 0-42""" ; mieroselera only sigmata which are large, but thin, 0-084 — o-i2""". Of this interesting species we have two specimens, one growing on an Astarie-sheW together with H. Levis, the other growing on a small Saxicava together with H. Koehleri and H. procumbens. The greatest extent to which the species reaches is about 10""", and the thickness is at most o-6mm. The colour (in spirit) is brownish red. The surface seems, when the sponge is undamaged, to be smooth. The dermal membrane is a thin film. Oscula and pores were not observed. The skeleton. The dermal skeleton consists of bundles of dermal spicules which stretch from the skeleton below to the surface, they thus lie between the apical parts of the long skeletal spicules; the spicules in the bundles are more or less penicillately spread outwards; the bundles are sometimes rather large, consisting of many spicules. The main skeleton is arranged as usual and consists of vertical acanthostyli, the longest of which stretch to the surface; at the base there is a small amount of spongin. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli which are divided into two groups, large and small; the large styli are straight or, generally, slightly curved near the base; they have a round, more or less swollen head and taper into a long and fine apex which generally is a little more abruptly pointed outermost; the head-swelling is beset with medium sized, blunt spines, and a short basal part has small spines, the rest of the style is smooth. The small styli are generally straight, they have a round head-swelling which is however less distinct than in the large styli, it is likewise beset with blunt spines, and the styli are spined in the whole or nearly the whole length, but the spines are dispersed outwards. The length of the large acanthostyli is about 0-30—0-83"""; they vary considerably in thickness from 0-020— 0-029 ram an<^ tms nas no relation to their length, the PORIFERA. III. IOI longest being often thin; the small styli have a length of 0-119— o-i6mm and a diameter at the head of o-02imm. The large styli are generally in size nearest the greatest length, the shorter of them, which are nearly intermediate between the large and the small, being rare. 2. The dermal spicules are long and straight strongyla, sometimes one end, and sometimes both may be slightly swollen, in the latter case the spicule approaching to a tylote; they are as a rule slightly polytylote. The length is 0-32 — 0-42 mm and the diameter 0-005— 0-007 mm. Some fine developmental stages were found which were monactinal. b. Microsclera are of one form, sigmata, which are rather curious; they are large but exceedingly thin, and they are more or less contorted up to a quarter of a turn, otherwise they are of the common shape. The length is 0-084 — °'12 mm ar>d the thickness o-ooi4mm. The sigmata occur through the whole tissue but are especially numerous at the surface. Locality: Station 9, 640 18' Lat. N., 270 00' Long. W., depth 295 fathoms; station 98, 65° 38' Lat. N., 260 27' Long. W., depth 138 fathoms. Both localities lie in the Denmark Strait. 45. H. Dujardinii Bow. PL X, Fig. 5. 1866. Hymeniacidon Dujardinii Bowerbank, Mon. Brit. Spong. II, 224, 38. 1867. Halisarca Dujardinii, Gray, Proc. Zool. Soc. 1867, 520. 1874. Hymeniacidon Dujardinii Bowerbank, 1. c. Ill, 95. PL XXXVIII, figs. 1—4. 1882. Bowerbank, Norman, ibid. IV, 92, 48. 1888. Dendoryx Dujardini, Topsent, Arch, de Zool. exp. et gen. 2, V bis, 115, PL VI, fig. 3, 12, 13 c. 1890. — — , Topsent, Mem. de la Soc. Zool. de Fr. Ill, 201. 1891. — — , Topsent, Arch, de Zool. exp. et gen. 2, IX, 528. 1892. , Topsent, Resultats des camp, scient. du Prince de Monaco, Fasc. II, 99. 1892. Myxilla radiata Bow. Topsent, (partim, the last passage), ibid. 109. 1894. Leptosia Dujardini, Topsent, Mem. de la Soc. Zool. de Fr., VII, yj. 1896. — , Topsent, ibid. IX, 123. 1896. — — . Topsent, Resultats scient. de la camp, du "Caudan", 275. 1901. — — , Topsent, Arch, de Zool. exp. et gen. 3, IX, 353. 1904. — , Topsent, Resultats des camp, scient. du Prince de Monaco, Fasc. XXV, 185, PL I, fig. 5- 1909. Hymedesmia Dujardinii, Luudbeck. Meddel. om Gronl. XXIX, 444. Tncrusting ; surface smooth; pore-sieves scattered on the surface. Spicula: megasclera; the skeletal spicules acanthostyli with a globular, more or less marked head, spined in the zvhole length, 0-083 — o-22""", not divided into two groups; the dermal spicules subtylota to strongyla o-i^g — 0'28""". No microsclera. Nearly all the specimens in my material of this species, and they are rather numerous, grow as thin incrustations on the shells of a species of Valdheimia. and the specimens of the Valdheimia were all living; one specimen grows on a mussel-shell, one on a Bryozoa, one on a stone with a speci- men of Petrosia crassa and finally one on a Voeringia. Otherwise it is recorded as growing on stones, io2 PORIFERA. III. shells of Bivalves, Hydroids, and once it is recorded (Topsent 1S92) as on an Inackus. The greatest extent to which the sponges in my material ordinarily reach is determined by the size of the Valdhciiiiia, and is thus about 20 mm, and the incrustations are as a rnle very thin, scarcely reaching 0'5'"m. The specimen on the stone has an extent of 25mm. The colour (in spirit) is generally pale yellow, sometimes deeper yellow or brownish. Topsent records (1. c. 1888) that it may sometimes be violet. The surface is smooth. The dermal membrane is delicate and transparent and without spicules; it is thin, but when it remains on the sponge in its normal position it is not at all fragile, and is easily separable; but in most cases the membrane is more or less destroyed, either quite wanting or remaining only as patches or rags; probably the membrane is in the living sponge soft and hence easily torn, but on hardening in alcohol it becomes much tougher. Topsent (1. c. 1888) speaks of "La peau epaisse" but he is here evidently thinking of the whole tissue occupied by the dermal spicules; in 1892, on the other hand, in the description of the specimens of Myxilla radiata which in 1904 he declares belong in reality to H. Ditjardinii, he describes a thin dermal membrane. Oscula and pores: Bowerbank says: "Oscula and pores inconspicuous", and Topsent (I.e. 1888) says: "Les orifices aquiferes sont petits". Oscula I have not observed, but pores I observed on the other hand in those specimens in which the dermal membrane was in good condition; the pores are some- what interesting; they are gathered in beautiful sieves which may be present in rather great numbers; the sieves are generally oval and are seen as slight, somewhat sharp-bordered impressions inclosing a sieve-like membrane; they are not very conspicuous and require a close examination to be detected, and they are best rendered visible when the sponge is a little dried. The sieves have generally a largest diameter of 08 — 2mm; the pores are dense-lying, more or less oval and of a diameter of 0-028— o-o8mm. The skeleton. The dermal skeleton consists of fibres, bundles or more loosely scattered spicules which stretch from near the base and up to the dermal membrane; it may be somewhat differently developed in different places, in some places it consists only of scattered spicules together with some few bundles, while in other places the spicules and bundles are much more crowded; sometimes also the spicules may form rather long fibres running horizontally below the dermal membrane; finally, as already pointed out by Topsent, the dermal skeleton is naturally most developed in the thickest specimens, as it alone occupies the space between the basal skeleton and the surface. The main skeleton consists of vertical acanthostyli with their heads placed on the substratum; they are some- what distantly arranged; at the base there is a distinct amount of spongin forming a more or less distinct basal lamella, and the spongin also stretches somewhat up along each acanthostyle, thus imbedding the lower part of it and forming a distinct coat. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli; they are straight, only rarely slightly curved; the head is globular, sometimes distinctly marked off, at other times less so on account of the shaft being rather thick below, but also in this latter case of a globular appearance; the shaft tapers evenly from the head to the point. The styli are spined in their whole length, only the spines are sometimes few and dispersed towards the point, and a short outermost part may then be smooth. The spinulation may vary much in different specimens being more or less dense; the spines are medium sized and reclined on the shaft, but radiating straight out or curved somewhat PORIFERA. III. 103 upwards on the head, and they may here vary somewhat in length. The size of the styli varies somewhat, but there are no groups; the length is 0-083— 0-22 mm and the diameter of the head is 0-012 — 0-02mm. The size may be somewhat different in various individuals, the styli sometimes not reaching over o-i5mm in length. 2. The dermal spicules are subtvlota varying to strongyla; they are straight and slender; when they are of tylote shape one end of the shaft is thinner than the other, and this thinner end has a distinct end-swelling, while the other end is more evenly and but slightly thickened; the shaft is generally of the same thickness in the whole length, but sometimes somewhat thickened in the middle. The length of the dermal spicules varies in all from 0-149— 0-28 n,m, an(^ tne diameter from 0-002— 0-005 mm, but the difference is not so great in the single specimens, as these spicules may vary to a rather considerable degree in different specimens; thus the following measurements were taken from different specimens: 0-149— 0-19 mm, o-i6 — o-20mm, 0-19— 0-24 mra, 0-18 — o-28mm and 0-20— o-28mra. Very often the larger spicules are strongyla or slightly tylote, while the smaller are more distinct tylota. Microsclcra are not present. Embryos. In many of the specimens embryos were found. They are globular and of an average diameter of 0-23 mm; they are often present in great numbers. Nearly all the specimens examined had spicules, only a single one without spicules was seen. The spicules are styli considerably smaller than those of the grown sponge; they were measured from 0-028— 0-078 mm in length and from exceedingly fine to o-oo8mm in diameter at the head; otherwise they are acanthostyli chiefly of the same shape as in the grown sponge, only the spines are less developed, in such a way, that the spicules may be termed coarsely and rather densely gritty. It will thus be seen, that the spicules first appearing in the embryo are the skeletal spicules; this was also to be expected, the same being the case in the Myxilleae, as I have shown in the second part of this work in several instances, in the genera Myxilla, Iophon and Forcepia, in the embryos of which the skeletal spicules are also the megasclera first appearing. Topsent declares on the contrary (1. c. 1888, no), just with regard to the present species, that the first developed spicules are the dermal, and he says further that this also holds good with regard to Myxilla incnistans. It is somewhat strange to me how he has got to this result; I can only imagine that he has examined embryos with very young and fine spicules, in which case these may perhaps be mistaken for dermal spicules. Locality: This species has been collected in rather great numbers; station 1, 62° 30' Lat. N., 8° 21' Long. W., depth 132 fathoms; station 6, 630 43' Lat. N., 14° 34' Long.W., depth 90 fathoms; station 25, 630 30' Lat. N., 54° 25' Long. W., depth 582 fathoms; station 27, 64° 54' Lat. N., 55° 10' Long.W., depth 393 fathoms; station 28, 65" 14' Lat. N., 55° 42' Long. W., depth 420 fathoms; station 35, 65° 16' Lat N., 55° 05' Long. W., depth 362 fathoms; further it has been taken at East Greenland, Forsblads Fjord, depth 50—90 fathoms (The Amdrup-Expedition 1900), and at the Faroe Islands, depth 30 fathoms (Th. Mortensen). The localities are situated in the Davis Strait, at East Greenland, the Eastern coast of Iceland and the Faroe Islands. Geogr. distr. H. Diijardinii was hitherto recorded from the Eastern coasts of Britain and Ire- land (Bowerbank); from the French coast of the Channel (Luc, Roscoff, Calvados) (Topsent), the Bay of Gascogne, depth 95 fathoms (Topsent), the coast of Provence at Ciotat (Topsent), at the Azores in depths of 69 and 28 fathoms, at 46° 47' Lat. N., 6o° 12' Long. W., depth 72 fathoms (Topsent), finally at io. PORIFERA. III. the coasts of North Africa, in the Bay of Gabes and at la Calle (Topsent). The species is thus hitherto known from 650 to 340 Lat. N., and between 6o° Long. W. and io° Long. E. As to the depth some of the specimens of the Iugolf Expedition are taken in considerably greater depths than those from which it was known hitherto; the greatest depth recorded was 95 fathoms, while it was taken by the Ingolf Expedition in depths down to 582 fathoms. Its bathymetrical range as known now is in all from the very coast even above low-water mark (Bowerbank) down to 582 fathoms. Remarks: If the rules of nomenclature were adhered to strictly, the present species should have a new name, as it is not identical with the well known Halisarca Dujardinii Johnst. Bower- bank thought, when he examined the present species, that Johnston had overlooked the spicules, and he identified it therefore with Dujardinii. Already Schmidt has noted (Zweites Suppl. zu den Spongien des adriat. Meer. 1866, 16) that this must be erroneous. Gray however in 1867 followed (1. c.) Bowerbank. Topsent in 1888 (I.e.) placed the species in the genus Dcndoryx, and referred it later correctly to his genus Leptosia, but he did not alter its name, which should properly have been done, since Bowerbank's determination was erroneous. As the species is well known now under the name Dujardinii I shall however make no change. 46. H. primitiva n. sp. PI. X, Fig. 6. Incrusting; surface smooth. Spicula: megasclera ; the skeletal spicules acanthostyli with a slight head-swelling, entirely spined or the larger with a smooth apical part, 0-119 — o-jj'""', not divided into two groups; the dermal spicules strongyla, slightly polytylote, 0-196 — 0-28""". No microsclera. This species grows incrusting on shells of Brachiopods, mussels and barnacles; it has a greatest extent of about 20 mm, the thickness is about 0-5 mm. The colour (in spirit) varies between dark yellowish and brown. The surface is smooth. The dermal membrane is a distinct but thin film; it was on my specimens often destroyed to a high degree. Some canals are seen shining through the membrane, and some oscula are present as circular openings not elevated over the level of the surface. The skeleton. The dermal skeleton consists of bundles or quite short fibres stretching from the main skeleton, often almost from the base, to the dermal membrane; the spicules in the bundles are penicillately spread towards the membrane and support it, but they do not pierce it. The mem- brane itself is not provided with spicules or at all events only with some few, lying singly and scattered; only around the oscula the structure is different; short fibres appear here in the membrane, stellately arranged all round the opening, towards which they unite in such a way, that the opening is surrounded by radiately arranged, but not dense-lying single spicules. The main skeleton is of the ordinary arrangement, the vertical acanthostyli are somewhat densely placed; the longest of them reach just to the dermal membrane. There is a considerable amount of spongin at the base, forming a more or less continuous basal layer. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli, which have only a slight head-swelling; they are straight or, when longer, slightly curved near the base; they are somewhat densely spined with spines of medium size; in the longer spicules the spines are small and scattered PORIFERA. III. I05 towards the apex, and a shorter or longer part may be smooth. The styli vary much in size but they are not divided into two groups. The length is 0-119 — 035 mm and the diameter at the base is 0-014 — o-027mm. The styli may vary somewhat in different individuals, in some they are more robust and more coarsely spiued than in others, and at the same time the smooth part towards the point is wanting or small. Also with regard to the size there is some variation, the greatest length being in some individuals o-27mm. 2. The dermal spicules are straight or slightly curved, cylindrical strongyla; they are slightly but distinctly polytylote and the ends are generally very slightly swollen, the swellings being as a rule scarcely perceptible. The length is in all 0-196— o-28mm, but there may be some variation between the individuals; the diameter is 0-0028— 0-005 mm. °- Microsclera are not present. This species is characterised towards H. Dujardinii by the size and shape of the acanthostyli and by the polytylote dermal strongyla. Locality: Station 6, 630 43' Lat. N., 140 34' Long. W., depth 90 fathoms; station 28, 650 14' Lat. N., 550 42' Long. W. , depth 420 fathoms; station 89, 640 45' Lat. N., 270 20' Long. W., depth 310 fathoms; further it has been taken at Iceland, depth 54 fathoms; East of the Faroe Islands, depth 160 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902). The localities lie in the Davis Strait, the Denmark Strait, between Iceland and the Faroe Islands and East of the latter. 47. H. longurius n. sp. PI. X, Fig. 7. Incrusting; surface smooth or nearly so, with scattered fore-sieves. Spicula: megasclera; the skeletal spicules acanthostyli with a small or no head, entirely spined or with a smooth apical part, 0'io — O'jO""", not divided into two groups ; the dermal spicules strongyla 0-22 — 0-298""". No microsclera. This species grows as thin but very extended incrustations on large Balani, on Brachiopods and one specimen on aPecten; both the Balani, the Brachiopods and the Pecten were living specimens. As the species grows along and round the Balani, it may reach to a greatest extent of not less than 75mm; the thickness does not reach 0-5 mm. The colour (in spirit) is yellowish or greyish yellow, in some specimens dark brown or even blackish brown, but probably this latter colour is due to a change produced later. The surface is smooth or at all events only with a few projecting spicules. The dermal membrane is a thin film resting on the skeleton below. Oscula I have not seen, but the pores are arranged in a somewhat interesting way; they are lying in pore-sieves which are generally circular; the sieves are surrounded by a very low wall and they are thus seen as slight, circular, sharply bordered impressions, the borders of which are only a little elevated over the surface; the whole formation is only little conspicuous, and is generally only to be seen when the sponge is half dried; in some specimens I could not detect pore-sieves. The pores are close-lying in the sieve and of an average diameter of 0-04 mm. The skeleton. The dermal skeleton is well developed; it consists of bundles and fibres of dermal spicules stretching from the main skeleton to the dermal membrane, the outermost spicules in the fibres are more or less penicillately spread; sometimes the fibres may stretch horizontally below the membrane for some distance. Around the pore-areas the spicules are radiately arranged and they The Ingolf-Expedition. VI. 3. 14 iq6 PORIFERA. III. stretch into the wall bordering the areas and are here arranged densely and parallel, forming thus a dense skeleton in the wall. In the membrane itself there are otherwise no spicules, or at all events only some single, scattered ones. The main skeleton is of the common construction consisting of vertical acanthostyli with the heads based on the substratum; the longest of them reach to the dermal membrane or even pierce it. At the base there is a slight amount of spongin. Spicula: a. Megasclcra. i. The skeletal spicules are acanthostyli which are straight or slio-htly curved near the base; the head is small but however generally somewhat distinctly swollen; in the small spicules it is as a rule not swollen; the styli taper into a long and fine apex. The spinulation is dense but the spines are somewhat small; in the longer spicules the spinulation is less dense, the spines become very small and scattered outwards, and in the longest a larger or smaller apical part, sometimes almost the half part, is smooth. The styli vary very much in size, but are not divided into groups. The length is crio— o-somm and the diameter of the head 0-014- 0-025 mm- 2- T5ie dermal spicules are straight or only slightly and somewhat irregularly curved strongyla; they are often more or less polytylote, but they may also be quite smooth; one end is a little thicker than the other, the thinner end has sometimes an elongate, more or less pronounced swelling, which is the more distinct the thinner the spicules are. The strongyla may vary somewhat in the different individuals, being in some considerably thicker and less slender than in others; in these thicker strongyla there is no end-swelling. Some very fine developmental stages were seen which were monactinal. The length is 0-22— o-2o,8mm and the diameter 0-003— 0-007 mm- Microsclera are not present. Locality: Station 32, the Davis Strait, 66° 35' Lat. N., 560 38' Long. W., depth 318 fathoms; Ice- land in 0fjord on the Northern coast, depth 18 fathoms (Ditlewsen) and at Hornsvig on the South- east coast, depth 84 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902). 48. H. aequata n. sp. PI. X, Fig. 8. Incrusting; surface smooth. Spicula: megasclera; the skeletal spicules acanthostyli with a small or no head, entirely spined, o-io — o-jo""", not divided into two grojips; the dermal spicules strongyla o'2i— 0-298 """. No microsclera. This species grows as a thin but extended incrustation on the lower side of a Lithothamnion. Its greatest extent may be estimated to about 40 mm but is in reality more, as the sponge follows the irregularities on the underside of the Lithothamnion; the thickness is about o-25mm. The colour (in spirit) is whitish brown. The surface is smooth without projecting spicules. The dermal membrane is thin and not separable. Oscula and pores were not observed. The skeleton. The dermal skeleton consists of bundles or fibres stretching from the main skeleton, generally quite from the base up to the dermal membrane, at which the bundles are spread in a penicillate way. The fibres have a more or less oblique direction, and when they are of some length they stretch horizontally below the dermal membrane. The main skeleton is of the ordinary arrangement consisting of erect acanthostyli with their heads on the substratum; the styli are some- what distantly placed. At the base there is a distinct though not copious amount of spongin. PORIFERA. III. 107 Spicula: a. Megasclera. 1. The skeletal spicules are somewhat slender aeanthostyli ; they are straight or, the longer of them, slightly curved and these latter have a small head-swelling; the small styli have a very slight head-swelling or often no swelling at all. The styli are somewhat densely spined with small spines, and they are all, both the large and the small, spined in the whole length; the spines are relatively largest iu the small styli. The length is 010— 0-30 mm and the diameter at the base 0-012 — 0-017 """■ The styles are not divided into two groups. 2. The dermal spicules are strongyla which have one end a little thicker than the other, and they are slightly fusiform, being a little thicker in the middle than towards the ends; they may sometimes be slightly polytylote, which is especially the case with the thinner (not fully developed) forms. The length is 0*21 — 0-298 mm and the diameter in the middle 0-004 — 0-007 mm. Microsclera are not present. This species is very difficult to characterise towards the three preceding ones, but it is no doubt distinct. From Dujardinii it is distinguished already by the dermal strongyla, as in Dujardinti there are always at all events some tylota among the dermal spicules; primitiva has longer, somewhat more robust styli with somewhat stronger spines, and distinctly polytylote dermal spicules; lo)igurius finally is easily distinguished by the long styli which are smooth in a shorter or longer apical part. Also the small styli without heads are characteristic for the present species. Locality: At Ikamiut in North Greenland. One specimen. 49. H. dermata n. sp PI. Ill, Fig. 17, PI. XI, Fig. 1. Incrusting ; surface smooth, bearing a number of conical, compressed oscular and pore-papi/lir. The dermal skeleton much developed, the main skeleton rather weak. Spicula: megasclera ; the skeletal spicules aeanthostyli zvith a small or no head, divided into hoo groups, large, only spined below, o-jo — o'4ij""", small, spined in the whole length o-io1/ — o'lj"""; the dermal spicules long strongyla o-jj—o'jj""". No microsclera. Of this species we have a couple of specimens growing on a branching Bryozoon, and one growing on a stone; the latter specimen is iucrnsting in the common way, but the specimens growing on the Bryozoon quite envelop the branches of this, and they also extend between the branches, filling the interspaces with their body, which however in these places is thin and plate-shaped. The greatest extent of the species is about 35 mi", and the thickness of the incrustation may reach 1-5 mm. The colour (in spirit) is whitish or yellowish white. The surface is smooth, without projecting spicules, it bears a number, smaller or greater, of conical papillae; these papillae are highly compressed and are generally lying quite down towards the surface with a flat side turned upwards, and the arrangement is then such, that the opening, which lies in reality in the summit, comes to lie at the summit of the side of the papilla, which is turned upwards. The dermal membrane is a thin and separable film; it has no skeleton proper, but the tissue lying below it, and which has horizontal fibres, is liable to be separated off together with the membrane, the whole thus giving the impression of a thick and solid membrane. Oscula and pores are certainly situated on the papillae mentioned; most of these show a rather large opening at the summit, while some others are more pointed and conical with a small 14* io8 PORIFERA. III. opening; I have not seen pore-sieves but the papillae with the large opening are in all probability pore-papilla?, the others being oscular papillae, the facts being thus as in H. verrucosa. The skeleton. The dermal skeleton; the skeleton formed by the dermal spicules is by far the most developed and it occupies nearly the whole body of the sponge; it consists of fibres which stretch from the main skeleton or quite from the base and obliquely towards the surface, but they run generally so obliquely, that they are for long distances more or less parallel with the surface, and the skeleton is on the whole rather irregular on account of the manner in which the sponge grows; the fibres are somewhat numerous and they are also rather strong, of a thickness up to cri2mm. The fibres stretch horizontally just below the dermal membrane and terminate in it, but there are no spicules proper to the membrane. The fibres lying below the membrane run together at the base of the oscular and pore-cones and continue up in the wall of these, forming thus a skeleton which consists of densely placed parallel spicules with the ends towards the opening of the cone. The main skeleton is somewhat weakly developed and consists as usual of acanthostyli with the heads based on the sub- stratum, but the styli are much scattered and not numerous. At the heads of the acanthostyli there is a very small amount of spongin. Spicula: a. Megasclcra. i. The skeletal spicules are acanthostyli which are divided into two well separated groups, large and small. The large styli are straight or slightly curved, the head is small or not at all developed; they taper evenly outwards but at the end they are abruptly pointed with a short point; they are spined only on the basal part at most in the lower half part; most of the spines, especially those on the head, are somewhat strong. The length is 0-30 — 0-417 nim and the diameter of the head o-oi8— o-022mm. The small styli are straight and spined in the whole length, but the spines are small and scattered in the outer part, otherwise they are relatively robust; these styli are somewhat uniform in size, the length being 0-107— 0-13 mm and the diameter of the head 0-014 — 0*019 mm. 2. The dermal spicules are long and straight strougyla with one end thicker than the other; they may be slightly polytylote; the ends may sometimes be very slightly swollen, especially in the thinner strongyla. The length is 0-33 — 04.5 mm and the diameter 0-006—0-010 mm. Microsclera are not present. This species is interesting in a certain respect; it resembles to a very high degree one of the species with chelse, viz. H. sty lata; the only differences, besides the want of the chelae, are that both the styli and the dermal spicules are slightly smaller in the present species than in stylata, but this is of no specific value; otherwise the growth, the surface with its papillae, the structure of the dermal membrane, the arrangement of the skeleton and the shape of both kinds of spicules agree very well in the two species, and if it were not for the difference in the possession and non-possession of chelae, and the difference in the structure of the dermal membrane, to which the want of the chelae seems to give rise, I should not hesitate in uniting them. As however I have otherwise never found, that the same species may be with or without chelse, I think it necessary to consider the present species as specifically distinct from H. stylata.1) It is to be remarked, that the specimens of both species are J) To be sure Topseut has described (Resultats du Voy. du S. Y. Belgica, Spongiaires, 1901, 18.) a species without sigmata as Lissodetidoryx spongiosa R. and D. var. asigmata, arid in the same place the author strongly advocates the view that sponge-species are capable of varying in such a way, that they may want a form of microsclera otherwise present in the species; I cannot at all agree with Tops en t in this new, and with regard to the examples he mentions (Hamacantha John- soni, Dcsmacella Pcachii) 1 have proved (The Ingolf Exp. VI, I. 1902) that the supposed varieties are distinct species, and with regard to H.Johnsom Topseut has himself in his work from 1904 admitted the specific validity of his former varieties. PORIFERA. III. 109 in a good state, and they have especially the dermal membrane undamaged, and further it must be noted, that the chelae in stylata are numerous and form a layer in the dermal membrane. Should the two species be considered as identical, it must be from the point of view, that the specimens of dermata were abnormal, but there is otherwise nothing to indicate such a state. Now one fact is very interesting, and it is that H. stylata is from the cold area (station 113, bottom temperature -M°o C), while the present species is from bottom with positive temperature. It is not for the first time that very nearly related, but distinct species are found one on negative the other on positive bottom (e.g. Gelliodes plexa and consimilis, The Danish Ingolf Exp. VI, 1; Asbestopluma pennatula and bihamatifcra, Cladorhiza abyssicola and gclida, Lissodendoryx complicata and vicina; ibid. VI, 2.). Locality: Station 2, 630 04' Lat N., 90 22' Long. W., depth 262 fathoms; Forsblads Fjord in East Greenland, depth 50—90 fathoms (The Amdrup Expedition 1900). The localities lie at East Greenland and West of the Faroe Islands. 50. H. tornotata n. sp. PL III, Fig. 18, PL XI, Fig. 2. Incrusting ; surface hispid. Spicula: megasclera; the skeletal spicules acanthostyli ?vith a more or less pronounced head, entirely spined but in the longer the spines very small outwards, o-ioy—o-ji""", not distinctly divided into two groups; the dermal spicules long tornota, generally with microspined end-parts, o'j2 — o-j?""". No microsclcra. This species is represented by four specimens, three growing on shell-fragments, the fourth on a Brachiopod; the former are rather small crusts while the latter covers the greatest part of the Brachiopod shell and has thus an extent of 20mm. The small specimens are about 07 mm thick while the larger one reaches to a thickness of about imm; this comparatively great thickness is reached on account of a special development of the dermal skeleton as mentioned below. The colour (in spirit) is light brown to brown. The surface is densely hispid from projecting dermal spicules; the small specimens are much more hispid than the large. The dermal membrane is inconspicuous and not separable. Oscula and pores were not observed. The skeleton. The dermal skeleton consists of large bundles of dermal spicules which stretch from the main skeleton to the surface, the spicules in the bundles are penicillately spread outwards and project beyond the surface for a rather long distance; seen from above the projecting spicules are almost stellately arranged. Such is the construction of the dermal skeleton in the small specimens, but in the large specimen the facts are somewhat otherwise; the dermal spicules are here more numerous and they are somewhat strongly interwoven, forming a dense and thick layer, and apparently lying without any order; only outermost they are arranged somewhat parallel, with the points projecting outwards; this layer may reach to a thickness of o-8mm. The difference in the development of the dermal skeleton in this species is, as will be seen, about the same as may also occur in H. Du/ardinii. The main skeleton is of typical construction, consisting of vertical acanthostyli with the heads on the substratum; they are placed rather densely. At the base there is an amount of spongin. IIO PORIFERA. III. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli which are not divided into two groups, in so far as intermediate forms occur, but as these are somewhat rare, the styli give the impression of falling into two groups; the large styli are straight or very slightly curved, they have a roundish head with moderately sized spines, the shaft has small spines which become quite gritty outwards; the small styli are generally straight, the head is less pronounced than in the large, the spines are larger and often distinctly reclined. The length of the styli is in all 0-107— 0-31 mm and the diameter at the head 0-014— o-02i1I,m. 2. The dermal spicules are long, straight, or somewhat, often irregularly, curved tornota; they are thickest in the middle and thus more or less fusiform; they show a curious feature, the end-parts being generally, but not always, somewhat roughened or micro- spined. The length is 032— 0*47 ram and the diameter in the middle 0-004 — 0-007 mm. Microsclcra are not present Locality: Station 81, 6i°44' Lat. N., 27° oo' Long.W., depth 485 fathoms; station 89, 640 45' Lat. N., 27° 20' Long. W., depth 310 fathoms; East of the Faroe Islands, depth 160 fathoms. The localities lie in the Denmark Strait, South-west of Iceland and at the Faroe Islands. 51. H. mucronella n. sp. PL HI, Fig. 19, PL XI, Fig. 3. Incrusting, but of somewhat massive appearance; surface hispid. The dermal skeleton strongly developed, the main skeleton weak. Spicula: megasclera ; the skeletal spicules acanthostyli divided into two groups, large with a very small head, only spined below, o-jo — 0'6j""", small, with a more distinct head, and entirely spined, o-ij — 0-178""" ; the dermal spicules tornota with one end with a mucro, o-j8 — o45p6""". No microsclcra. Of this species we have only one specimen which grows on a fragment of a Sipho; the sponge is of a somewhat massive shape as it does not incrust the shell-fragment but is only fixed on it and is for the rest somewhat filled with bottom material; it thus shows a growth similar to that in H.grandis, though it is much less filled with foreign particles. On account of large cavities in the sponge the consistency is somewhat bladder-like. The specimen has an extent of 17 n,m and a height of about gmm The colour (in spirit) is dark greyish brown. The surface is strongly and densely hispid from projecting dermal spicules. Oscula and pores were not observed. The skeleton. The dermal skeleton; the skeleton formed of the dermal spicules is strongly developed and occupies the greatest part of the sponge; it consists of fibres running everywhere but chiefly in the direction from the base, or else from some part of the main skeleton, towards the surface, the fibres may thus attain a relatively great length; in the dermal membrane the spicules form penicillately spread bundles, the spicules of which pierce the membrane; seen from above the spicules in the bundles appear almost stellately arranged; in places where the membrane stretches over the large cavities, fibres pass horizontally just below it, and the bundles seem here to originate from these fibres. The sponge-body has, as said, many large cavities and the fibres are found therefore in the parts of the tissue separating these cavities. The main skeleton is not much developed; it consists of acanthostyli based with their heads partly on the shell at the base of the PORIFERA. III. in sponge and partly on the imbedded foreign particles, such as large sponge-spieules, gravel and the like, which particles must be considered therefore also as substratum for the sponge; the acanthostyli placed on the imbedded material ma}' point in every direction, and the main skeleton is, according to the manner of growth of the sponge, quite irregular. At the head of each acanthostyle there is a small, but distinctly observable amount of spongin. Spicula: a. Mcgasclera. i. The skeletal spicules are acanthostyli, divided into two groups, large and small; the large styli are straight or slightly curved near the base; the head is very small or almost quite absent, the basal part has some small or moderately sized spines, but only for a short distance, the remainder of the shaft being smooth or slightly and imperceptibly gritty. The length is 0-40 — o-65mm and the diameter at the base 0-017— o-02imm. The small acanthostyli are generally straight with a slight but distinct head-swelling; they are densely spined in the whole length, the spines on the head being the largest The length is 0-14— o-i78mm and the diameter of the head is 0-017 mm. 2. The dermal spicules are tornota but of a characteristic shape; one end is pointed in the way common for tornota and not very short, the other end is shorter and more roundish pointed and has a very distinct mucro; the latter end is somewhat thicker than the former; the tornota are long, straight or nearly so and slightly thicker in the middle than towards the ends. The length is 0-38— 0-596"™ and the diameter in the middle 0-005 —o-oi 1 ram ; tne intermediate sizes are by far the most common. Microsclera are not present. Locality: At East Greenland, 70° 32' Lat. N., 8° 10' Long. W., depth 470 fathoms (The Ryder Expedition 1891—92). Above I have described 51 species of Hymedesmia of which only seven are determined as previously described species; these are: H. Koehlcri Tops., occulta Bow., baculifera Tops., crux O. Schmidt, fili/era O. Schmidt, mucronata Tops., and Dujardinii Bow. I have tried to find out the other previously described species, and I think that at all events most of them are enumerated in the following list: 1866. H. zetlandica Bow. Mon. Brit. Spong. II, 152, III, PL XXI. figs. 1—7. « — paupertas Bow. ibid., II, 223, III, PI. XXXV, fig. 4—8 (Hymeniacidou). 1875. — vidua O. Schmidt. Jahresber. der Comm. zur wissensch. Unters. der deutsch. Meere in Kiel fiir 1872—73, 120. (Spirastrella); Thiele, Arch, fiir Naturgesch. 1903, I, 393, Taf. XXI, Fig. 27. 1882. — Peachii Bow. 1. c. IV, 64. PI. XIII, figs. 5-12. 1885. — ma mm 1 la r is Frstdt. Kgl. Sv. Vetensk. Akad. Handl. 21, 6, 32, Tav. Ill, Fig. 3 a— h. (Nastatus); Thiele, Arch, fiir Naturgesch. 1903, I, 389, Taf. XXI, Fig. 22 a— d. 18S7. — pustula Frstdt. Ofvers. Kgl. Vet. Akad. Forh. 1887, No. 1, 27, (Espcria). 1903. — prostrala Thiele, Abhandl. Senckenb. nat. Gesell. XXV, 955, Taf. XXVIII, Fig. 20. — norvegica Thiele, Arch, fiir Naturgesch. 1903, 1, 390, Taf. XXI, Fig. 23 a— c. (perhaps a Stylostichon). 1904. — mutabilis Tops. Resultats des camp, scient. du Prince de Monaco, Fasc. XXV, 166, PI. XIV, fig. 3. {Hymeraphia). « — Schmidti Tops, ibid., 1S9, PI. XV, fig. 9. (Lrptos/a). 112 PORIFERA. III. 1904. H. raphigeua Tops. Resultats des camp, scient. du Prince de Monaco, Fasc. XXV, 192, PI. XV, fig. 7. (Leptosia). — obtusata Tops, ibid., 193, PI. XV, fig. 6. {Leptosia). — acerata Tops, ibid., 193, PL XV, fig. 5. (Leptosia). 1(p^ _ tcnuissima Dendy, Rep. on the Pearl Oyster Fishery of the Gulf of Manaar, III, 169, PI. XI, fig. 5. (Myxilla). — areolata Thiele, Zool. Jahrb. 1905, 452, Taf. 31, Fig. 23, 68 a— d. 1906. — land/era Tops. Bull, du Mus. d'hist. nat. 560. (Leptosia). The number of species seems thus at present to be about seventy; this is already a large number and there is reason to believe, that many more species will be described in the future. Earlier Expeditions paid often but little attention to the insignificant crusts, which is the shape of most Hymedesmia species; it is first in the work of Topsent from 1904 that a greater number of incrusting species of various genera is recorded, and the author says expressly, that this fact is due to the care with which he examined stones, corals etc. brought home. The Ingolf Expedition laid the greatest stress on procuring all small and incrusting sponges, and hence our material is very rich. Under these circumstances when the number of species must be expected to increase in the future to some degree, it is of the greatest importance, that the new species are described thoroughly, and the spicules ought always to be figured, so that the affinities of the species can be judged. I shall therefore try to give here an analytical table of all the above enumerated species; this table is of course only an attempt, and I do not think that a species can be definitely determined only by its aid, but I think however it may be useful. Table of the Species of Hymedesmia. 1. Microsclera present — No microsclera 2. Microsclera only chelse arcuatse (sometimes transformed to spined rods) Microsclera chelse arcuatae together with sigmata, or sigmata alone or rhaphides 3. The chelae of common shape — The chelae spined or quite transformed 4. The dermal spicules genuine strongyla — The dermal spicules of other forms, at all events not quite genuine strongyla. 5. The acanthostyli not divided into two groups — The acanthostyli somewhat distinctly divided into two groups 6. The dermal strongyla more or less distinctly polytylote — The dermal strongyla not, or not distinctly, polytylote 7. The chelae somewhat strongly curved, 0-028— 0-050 mm, the acanthostyli with blunt spines on the head Koehleri Tops. — The chelse less strongly curved 8. 8. The chelse with somewhat long, free alse, 0-045— 0-054 mm lacera — The chelse smaller, somewhat like palmate chelse 9- 9. The acanthostyli strongly spined, especially at the head, chelse 0-033— 0-038 mm . storea — The acanthostyli less strongly spined, chelae 0-028 mm lamina 2 59 3 45 4 43 5 21 6, 13 7 10, PORIFERA. III. "3 10. Surface with low warts or long papillae n. — Surface simple 12. n. Surface with low warts, dermal strongyla long and straight verrucosa — Surface with long papillae, dermal strongyla robust with a double curvature. . . filifcra Schmidt. 12. The acanthostyli only spined on the head norvcgica Thiele. — The acanthostyli spined in the lower half part mollis 13. The chelae strongly, nearly semicircularly curved curvichela — The chelae less strongly curved 14. 14. The dermal spicules polytylote, chelae large, 0-052— 0-064 mm, the end-parts some- what recurved ritgosa — The dermal spicules not polytylote, chelae smaller 15. 15. The acanthostyli strongly spined in the whole length splenium — ■ The acanthostyli not entirely spined 16. 16. The large acanthostyli spined towards the apex, chelae 0-032— 0-037 ram, the free part of the shaft about one third of the length tenuicula — The large acanthostyli at most spined in the lower half part 17. 17. The small acanthostyli distinctly curved 18. — The small acanthostyli straight 19. 18. The acanthostyli reaching to o-65mm, chelae somewhat strongly curved, 0-035— o-044mm similis — The acanthostyli reaching to 0-42 mm, chelae less curved, 0-037""" paupertas Bow. 19. The acanthostyli long, reaching to 0-95 mm, the dermal spicules slightly tending towards tornota nummulus — The acanthostyli shorter, the dermal spicules pure strongyla 20. 20. The acanthostyli reaching to 0-63 mm, the dermal strongyla 0-35— 0-52 mra, surface with papillae sty lata — The acanthostyli reaching to 0-38 mm, the dermal strongyla 0-26 — 0-32 mm, surface simple dubia 21. The dermal spicules diactinal (at all events not distinctly monactinal) 22. — The dermal spicules monactinal 42. 22. The dermal spicules tornota 23. — The dermal spicules oxea or tylota 32. 23. The dermal spicules centrotylote tornota lanci/era Tops. — The dermal spicules not centrotylote 24. 24. The tornota with unequal ends 25. — The tornote with equal ends 26. 25. The large acanthostyli only spined at the base, o-24mm, chelae o-oi8mm prostrata Thiele. — The large acanthostyli a little more spined, 0-45 mm, chelae 0-03 mm Peachii Bow. 26. The large acanthostyli spined in about the whole length 27. — The large acanthostyli spined only near the base 31. 27. The chelae of ordinary shape 28. — The chelae extraordinarily flat platy chela 28. Surface with papillae, tornota o-36mm, chelae 0-024™"' mamviillar/sFTstdt. — Surface simple 29. 29. The acanthostyli reaching to 0-53 mm, the tornota 0-17— 0-22 mm, chelae with slightly recurved end-parts 0-021 — 0-054 mm perforata — The acanthostyli not reaching over o-35mm 30. The Ingolf-Expedition. VI. 3 15 PORIFERA. III. 114 30. The acanthostyli reaching to 0-35 mm, tornota 0-22—0-32 mm, chelse somewhat strongly curved 0-024— 0-038 mm procumbens — The acanthostyli reaching to o-298mm, tornota 0-16— o-i7mm, chelse less strongly curved, 0-041— o-o52mm clavigera 31. Surface with papillae, acanthostyli reaching to o-59mm, tornota o-32-o-50mra, chela; somewhat palmate-like, 0-025— o-030mm basispinosa — Surface simple, acanthostyli reaching to 0-92 mm, tornota 0-23— o-28mm, chela; of ordinary shape, 0-025— 0-045™' longistylus 32. Dermal spicules oxea 33- — Dermal spicules tylota 35- 33. The acanthostyli almost entirely spined, chelse 0-025 mm areola fa Thiele. — The acanthostyli only spined near the base 34. 34. The acanthostyli reaching to ri9mm, chelse 0-034— 0-040™™ occulta Bow. — The acanthostyli reaching to 0-65 mra, chelse strongly curved, 0-028— 0-037 mm simillima 35. The acanthostyli almost smooth, only slightly spined at the base, chelse 0-045 0-052 mm lavistylus — The acanthostyli more spined, often entirely 36. 36. The acanthostyli divided into two groups brae tea. — The acanthostyli not divided into two groups Zl- 37. The acanthostyli varying in size, reaching to 0-25 mm 38. — The acanthostyli rather uniform in size, not reaching over o-i3",m 39. 38. The acanthostyli somewhat robustly spined, dermal tylota not or only slightly polytylote baculifcra Tops. — The acanthostyli more finely spined, dermal tylota polytylote levis 39. The acanthostyli truncate at the point truncata — The acanthostyli not truncate at the point 4°- 40. The tylota distinctly polytylote, 0-148 ram tenuissima Dend. — The tylota not, or not conspicuously polytylote, length 0-19™" or more 41. 41. The acanthostyli without any neck-shaped constriction at the base, the tylota o-io — 0-23 mm Bower banki — The acanthostyli with a neck-shaped constriction at the base, the tylota 0-30—0-40 ram latrunculioidcs 42. The dermal styli polytylote, the acanthostyli not divided into two groups,' chelse 0040— 0-050 mm irregularis — The dermal styli not polytylote, the acanthostyli divided into two groups, chelse 0023— 0-035 mm proximo 43. The chelse transformed to spined rods vidua Schmidt. The chelse less transformed, more chel-shaped, or only spined 44. 44. The chelse of normal shape but spined crux Schmidt. — The chelse more transformed, somewhat asteriform acmgma 45. Microsclera chelse and sigmata 46. — Among the microsclera no chelse 58. 46. Sigmata only of one form 47. Sigmata of two forms 56. 47. The acanthostyli of uniform size, about o-i3mm, strongly spined, sigmata in bundles zetlandica Bow. The acanthostyli longer, sigmata not in bundles 48. PORIFERA. III. 115 48. The chelae spined and transformed Schmidti Tops. — The chelae not spined 49. 49. The chelae of two forms, ordinary and peculiar mucronata Tops. — The chelae only of one form 50. 50. Sigmata rather large, not below 0-028 ",m and generally much larger, surface with papillae or warts 51. — Sigmata small, not above o-o20mm, surface simple 54. 51. Surface with warts, sigmata about o-imm, chelae of two forms, large o-025mm, small o-oi2 mra pustula Frstdt. — Surface with long, cylindrical papillae, chelae of one form 52. 52. Sigmata nearly plane, dermal tylota 0-29— o-38mm, sigmata 0-058— 0-075 m,n trichoma — Sigmata not plane 53. 53. The acanthostyli 0-41 — 0-75 mm, dermal tylota 0-48— o-8omm, sigmata 0-031— 0-096 mm grandis — The acanthostyli o-ii — 0-31 mm, dermal tylota 0-26— 041 mm, sigmata 0-028— 0-050 mm digitata 54. The dermal spicules thin styli, sigmata circularly curved, nearly plane, 0-014 — 0-017 mra pugio — The dermal spicules not styli 55. 55. The dermal spicules tornota 0-15— 0-19 mm, sigmata 0-014— 0-017 mm consanguinea — The dermal spicules tylota 0-23 — cv28mm, sigmata o-020mm mutabilis Tops. 56. The large sigmata somewhat baud-shaped, peculiarly curved, the small sigmata plaue cultrisigma — Both the large and small sigmata of ordinary shape 57. 57. The large sigmata 0-18— o-2o8mm, the small 0-06— 0-089™'" macrosigma — The large sigmata contorted, 0-021 — 0028 mm, the small sigmata plane 0-014 mm. . planca 58. Microsclera only sigmata tenuisigma — Microsclera only rhaphides rhaphigena Tops. 59. Dermal spicules strongyla or tylota 60. ■ — Dermal spicules tornota 65. 60. The acanthostyli truncate at the point obtusata Tops. — The acanthostyli not truncate at the point 61. 61. The acanthostyli generally with a globular head, 0-083 — 0-22 n,m, the dermal spicules strongyla to subtylota and there are always subtylota present Dujardinii Bow. — Dermal spicules strongyla 62. 62. The acanthostyli not divided into two groups 63. — The acanthostyli divided into two groups, the dermal spicules long, 0-33— 045 mm dcrmala 63. The acanthostyli entirely spined aequata — The acanthostyli with a smooth apical part 64. 64. The acanthostyli o-n — 0-35 mm, dermal strongyla polytylote, 0-149 — 0*28 mm pri»iitiva — The acanthostyli o-io — 0-50 mm, dermal strongyla smooth or polytylote, o-22— 0-298 mm longurius 65. The dermal tornota not polytylote, generally microspined at the end-parts .... tornotata — The dermal tornota not with spined ends 66. 66. The acanthostyli 0-14— 0-38 ram, the tornota slightly polytylote accrata Tops. — The acanthostyli 0-14— 0-65 ram, divided into two groups, the tornota with a mucro at one end mucronella Four species in Bowerbank's Monograph could perhaps also be taken into consideration, viz. Hymeniacidon perarv/atus (III, PI. XXXI, figs. 11 — 16) which would in such a case perhaps be related to H. occulta and simillima; but it is possible that the species is an Ectyodoryx. Hymedesmia pansa 15* n6 PORIFERA. III. (IV, PI. I, figs, i— 4) has long, monactinal dermal spicules; it seems to be a Hymedesmia or an Eurypon. Hymedesmia pilata (IV, 59, PL II, figs. 1—4), which seems to have no dermal spicules and only sigmata for microsclera, is I think an Eurypoii. Finally Hymedesmia pulchella (IV, 61, PI. II, figs. 5—8) seems to be likewise an Eurypon. Hymeniacidon paupcrtas Bow. (Ill, PI. XXXVII, figs. 4—8) I have included in the above table as I take it to be a Hymedesmia, and I think the Myxilla paupertas recorded by Topsent (1904, Fasc. XXV, 168) is another species. The Hymedesmia areolata Thiele mentioned by Kirkpatrick (Nat. Antarc. Exp. Nat. Hist. IV, PI. 22, figs. 3—3 c) cannot I think be a Hymedesmia and must accordingly be another species. Thiele (Abhandl. Senckenb. nat. Gesell. XXV, 1903, 955) thinks that Myxilla veneta O.Schmidt is identical with fasciculata Lieberk, and is a Hymedesmia ; I have examined a specimen of Myxilla fas cictdata send from Professor von Mare nzeller; it is correct that the species incrusts the chitinuous tubes of Stephanoscyphus, but it has otherwise a reticulate skeleton and is no Hymedesmia; M. veneta I do not know. Hymedesmia norvegica Thiele, which I have included in the above table, is perhaps not a Hymedesmia as it has short skeleton columns; it would thus be a Stylostichon. Hymenancora n. g. Incrusting, thin forms. The external appearance, the skeleton and the megasclcra quite as in Hymedesmia ; the microsclera arc ancorm zuhich may be either anconr spatidiferce or unguiferce ; some- times two forms of ancora- occur; to the ancorcs sigmata are sometimes added. In the introduction to the second part of this work I have, in accordance with the opinions of Levin sen, advanced the view, that species with ancorse and species with chelae should not remain in the same genus, and in accordance herewith I emended the genera Desmacidon and Homoeodictya, Myxilla and Lissodendoryx, and according to the same view I have created the genera Ectyodoryx and Ectyomyxilla (Meddel. om Gronland, XXIX, 1909, 444), the first with chelae, the latter with ancorse. Also the genus Hymedesmia has hitherto included species with chelae and species with ancorse, and it is to comprise these latter species that I create the genus Hymenancora which is in all other respects similar to Hymedesmia. So far as I am avare the genus comprises at present the following species: 1 1892. H. Pecqueryi Tops. Resultats des camp, scient. du Prince de Monaco, Fasc. II, no, PI. XI, fig. 8 {Myxilla). « H minima Tops, ibid., 114, PI. XI, fig. 2—3. (Hymeraphia). 1904. H. biscutclla Tops, ibid., Fasc. XXV, 191, PI. XV, fig. 3. (Leplosia). H. umbellifera Tops. ibid. 192, PI. XV, fig. 4. (Leptosia). 1905. H. laevis Thiele, Zool. Jahrbiicher, 1905, 453, Taf. 31, Fig. 69 a— f. (Hymedesmia). H. tenuissima Thiele, ibid. 454, Taf. 31, Fig. 70 a — f. (Hymedesmia). 1907. H. cxigua Kirkpatr. Ann. Mag. Nat. Hist. 7, XX, 273, and 1909, Nat. Antarct. Exp. IV, PI. XXII, fig. 4, PI. XXVI, figs. 2 a— f. (Hymedesmia). PORIFERA. III. II7 1907. H. rufa Kirkpatr. Ann. Mag. Nat. Hist. 7, XX, 274, and 1909, Nat. Antarct. Exp. IV, PI. XXII, fig. 5, PI. XXVI, figs. 3 a — e. (Hymcraphia). H. interjecta mihi H. conjungens mihi H. tenuisclera mihi H. duplicata mihi. I do not see the slightest reason why H. minima Tops, and H. rufa Kirkpatr., both placed by the authors in Hymcraphia, should not belong to Hymenancora. 1. H. interjecta n. sp. PI. XI, Fig. 4. Jncrusting; surface slightly hispid. Spicula: megasclcra; tlic skeletal spicules acanthostyli without a real head-swelling, spined in the whole length, they are divided into two groups, large o-j? — 0-47 """, small 0-/4—0-16""",- the dermal spicules tylota or subfylota o-jo—o-j?"""; microsclera two forms, ancorce spatulifcra with three teeth, 0-025 — 0-045""", sigmata 0-06 — 0-128""". Of this species we have two specimens; one grows on a dead branch of an Oculina together with H. procumbeiis and specimens of Tedania, Eurypon and Latrunculia : the other specimen, which is very small, grows on a pebble. The largest specimen is extended along the Oc7ilina-brs.nch. and is therefore of a lengthy shape and has a greatest extent of 22 mm; it is exceedingly thin. The colour (in spirit) is greyish or brownish. The surface is in the present state of the sponge slightly hispid. Abont the dermal membrane, pores and oscula I can say nothing. The skeleton. The dermal skeleton seems to consist of bundles and scattered spicules. The main skeleton is, so far as I could observe, constructed in the ordinary way of vertical acanthostyli piaced on the substratum, but the styli are somewhat scattered and the dermal skeleton is therefore the most developed part of the whole skeleton. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli which are somewhat distinctly divided into two groups. The large styli are straight or generally somewhat curved near the base; the base is a little thickened, but there is no head-swelling present, and they taper into a long and fine apex; the styli are spined in their whole length, but the spines are only at the base of larger size, they decrease in size outwards, and the shaft and apex are only gritty; the larger spines at the base are generally curved upwards in a somewhat characteristic way. The small styli are principally of the same shape as the large, but they are often straight, and the spines are relatively larger, the head also is still less developed than in the large. The length of the large styli is 0-37 — 047 mm with a diameter at the base of 0-020— 0-023 mm. The small styli have a length of 0-14 — o-i6mm and a diameter at the base of 0-020 mm. 2. The dermal spicules may best be termed tylota; they are straight or very slightly curved and somewhat robust, the end-swellings are very small but how- ever always perceptible. The length is 0-30— 0-47""", and the diameter of the shaft 0-007— o-oiomm. b. Microsclera are of two forms, ancoroe spatuliferse and sigmata. 1. The an corse have a curved shaft and three elliptical teeth at each end, but the most remarkable feature is, that they have only very n8 PORIFERA. III. narrow alae or these may be quite absent; by this fact these aucorae get some resemblance to arcuate chelae and it seems that they also in reality must be nearly related to these. The length of the ancorae varies much, it is 0025— 0-045 mm, an^ tne thickness of the shaft is about 0-002— 0-005 mm. 2- The sio-mata are of ordinary shape and more or less contorted; they have a length of 0-06—0-128 n'm and a thickness of 0-004 — 00065 mm. The microsclera seem to occur through the whole tissue. Locality: Station 54, South of Iceland, 630 08' Lat. N., 150 40' Long. W., depth 691 fathoms; station 98, in the Denmark Strait, 650 38' Lat N., 260 27' Long. W., depth 138 fathoms. Remarks: As said the ancorae in this species seem to be nearly related to the chelae arcuatae on account of the very narrow and, so far as I could see, sometimes quite wanting alae, but they are however true ancorae. In Part II of this work p. 3 I have stated that I consider the ancorae and chelae arcuatae as nearly related spicula and as having been derived from a common original form of spicule. It is well known, that the chelae arcuatae may be more or less ancora-like, but being at the same time true chelae, and many examples of this are given in the preceding descriptions. As one of the most ancora-like chelae I have examined I may note the chela in Hymedesmia Bowcrbanki. The alae do not go here evenly over into the hinder side of the shaft but are somewhat incurved at the shaft, so that in a side view the "tuberculum" is seen quite surrounded by the outer contour of the ala; and so far as I could see the shaft is a little edge-like dilated towards the ends; these spicules are however true chelae. Should there be found in the genus Hymedesmia forms of micro- sclera which were intermediate between aucorae and chelae arcuatae, and this seems not impossible, it would be of great interest, and it would seem to indicate at the same time, that Hymedesmia is a genus of old origin, as already alluded to from other reasons under H. aenigma. 2. H. conjungens n. sp. PI. XI, Fig. 5. Incrusting; surface somewhat hispid. Spicula: megasclera; the skeletal spicules acanthostyli without head-swelling, they are divided into two groups, large, spined nearly in the zvhole length or only with a small apical part smooth, 0-29 — 0-4/""", small, entirely spined, o-u—o-ij"""; the dermal spicules tylota zuith pointed end-swellings, 0-16 — o-22mm; microsclera two forms, ancora spatuliferff with three teeth, 0-022 — o'o^2""", sigmata o'ojj — o~o^^mm. We have one specimen of this species growing on a living Pecten together with specimens of Melonanchora emphysema, Hymedesmia perforata and procumbeus, a Crella, an Eurypon and a Plocamia. It forms an incrustation of an extent of about I5mm, and it is very thin, not reaching o-5mm. The colour (in spirit) is light brownish grey. The surface is somewhat hispid from projecting spicules. The dermal membrane is a thin, transparent film, resting on the skeleton below. Oscula and pores: larger and smaller, simple circular openings are seen in the dermal membrane representing I think both oscula and pores. The skeleton. The dermal skeleton consists of bundles of dermal spicules stretching up to the dermal membrane and supporting it, the spicules in the bundles being somewhat penicillately spread outwards; the bundles are generally not large, consisting only of relatively few spicules. There are PORIFERA. III. "9 no horizontal spicules in the membrane itself. The main skeleton is constructed as usual of acantho- styli with their heads placed on the shell, the longest of them reach to the dermal membrane and project beyond it. At the base there is a small amount of spongin. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli which are divided into two groups, large and small; the large styli are generally slightly curved, they are a little thickened at the base, but there is no head-swelling, they taper only slightly outwards and the point is somewhat short; the styli are spined in almost the whole length, only a small part of the apex being smooth or nearly smooth; at the base the spines are of medium size and numerous, outwards they are small, nearly gritty, and more scattered. The small styli are mainly of the same shape as the large, they are straight or slightly curved and have likewise no head-swelling, but they are spined in the whole length. The length of the large styli is 0-29— 0-41 mm with a thickness at the base of 0-016— cro2 1 n,ra, the small styli are cru— o-i3mm long with a diameter at the base of o-on— ooi4mm. 2. The dermal spicules are tylota with the swollen ends pointed like toruotes; the shaft is slender and generally straight, sometimes it is very slightly polytylote; the ends are distinctly but not much swollen, and they are pointed in such a way that the spicule might be termed a tornote were it not for the swellings. The length is o-i6— o-22mm, and the diameter of the shaft is 0-0028 — o-oo4mm. b. Microsclera are of two forms, ancorae spatuliferse and sigmata. 1. The ancorae resemble those in interjecta, but they are a little less curved or the curve is distinctly localized in the middle of the shaft; they have three elliptical teeth at each end, the alse are not large but distinct and always present. This ancora is thus evidently related to that in interjecta, but it is less chel-like. The length is o-022— 0-042 m:n and the thickness of the shaft is 0002— 0-004 mm; the large ancorae are by far the most numerous while the smaller are seen only rarely. 2. The sigmata are of ordinary shape and they are contorted, generally a quarter of a turn. The length is 0-035— °'°4 5 mm an<^ tne thickness about o-oo28mm. The sigmata occur in the tissue of the sponge but not in the dermal membrane, the ancorae occur also in the tissue but especially in the dermal membrane and here rather numerously. This and the preceding species are nearly related, but they are characteristically different in the shape of the dermal spicules, the size of the sigmata and also in the shape of the ancorae. Locality: South of Iceland, 630 21' Lat. N., 16° 22' Long. W., depth 296 fathoms (The Fishery investigation steamer "Thor"). 3. H. duplicata n. sp. PI. XI, Fig. 6. Incrusting ; surface hispid? Spicula: megasclera; the skeletal spicules acanthostyli with a small but distinct head-sivelling, the largest only spined at the base, the shorter they are the longer a part is spined, and the shortest are spined in the whole length, 0-12 — o-^y"1"1, not divided into two groups; the dermal spicules tornota 0-238— 0-31""" ; microsclera ancora: spatulifera of two forms, large, with j — 6 teeth, 0-062—0-071""". small, with S — // teeth, 0-032 — 0-038""". This interesting species grows as thin incrustations on Brachiopod-shells; its greatest extent is 11™ and the thickness is about o-25mm. The colour (in spirit) is whitish or light yellowish. The surface is in the present condition of the sponge strongly hispid from projecting acanthostyli, but it I2Q PORIFERA. III. is probably not so in the fresh state. The dermal membrane seems to be quite wanting in the speci- mens, so that I can say nothing about it or about pores and oscula. The skeleton. The dermal skeleton; as the dermal membrane is quite or nearly quite wanting I can say only little about the dermal skeleton; it seems to be of a construction like that found in the preceding species and thus consists of bundles of spicules stretching from the main skeleton to the dermal membrane. The main skeleton is quite of the common construction, the acanthostyli reach to the surface and they project as said beyond it. A small amount of spongin is visible at the sub- stratum around the heads of the acanthostyli. Spicula: a. Megasclera. i. The skeletal spicules are acanthostyli of a somewhat characteristic shape; they have a head-swelling which is not large, but generally distinct, they taper evenly into the apex, but the point is a little more abrupt. The largest styli have only spines below; the head is beset with somewhat robust spines, and there are very small spines on the part just above the head; the shorter the styli are the more spined they are and the smallest styli are spined near to the point. The spines on the head are blunt, giving the head in the large styli a characteristic appear- ance; the spines of the shaft are relatively largest in the small styli. The styli vary much in length, but they are not divided into two distinct groups. The length is 0-12— o-47mm, and the diameter of the head 0-017 — o-037mm. The smallest styli are the most numerous. 2. The dermal spicules are slender and straight, or very slightly curved tornota, they are of the same thickness in the whole length; the ends generally form typical tornotal points, only sometimes the shape is less pronounced. The length is 0-238— 0-31 mm and the diameter is 0-0028— 0-004 """• D- Microsclera; these are ancorse spatuliferae of two forms and sizes, large and small; they are both very beautiful spicules. 1. The large ancors have a very slightly curved shaft and five to six elliptical teeth at each end; there are somewhat narrow alae on the shaft, reaching a little longer towards the middle than the teeth. Sometimes the number of teeth at each end is not equal, but may be five at one and six at the other end; also some irregularity may be found, and when there are six teeth, generally one or two are a little smaller than the others. The length is 0-062 — 0-071 mm, and the diameter of the shaft is 0-004 — 0-007 m"\ 2- The small ancorse have a shape somewhat similar to that of the large, but they have eight to eleven teeth at each end; the number of teeth may also here be different at the two ends; there are small alae on the shaft, but they are not directed to the sides but backwards, they are thus not or almost not seen when the ancora is viewed from in front, and they are on the whole difficult to see; from the fact that they are directed backwards they get a position similar to the falxes of the teeth, and teeth seem in reality sometimes to be formed here, so that there is a circlet of teeth all round; the construction recalling what is found in the ancorse of some of the Iotrochota species, e. g. / rotulancora (The Danish Ingolf Exp. VI, 2, Porifera, Part. II, 191, PI. XVIII, fig. 6 c — e). The length is 0-032— 0-038 mm, and the thickness of the shaft 0-003 ram. Of this ancora some developmental stages were seen; they showed a dilatation with beginning teeth at each end, and they thus resemble the developmental stages of the ancora in the mentioned Iotrochota species. The microsclera occur in the tissue of the sponge, and to judge from a single place on one of the specimens they also occur in the dermal membrane in somewhat great numbers; the small ancorse are by far the most numerous. PORIFERA. III. 121 This species is related to H. umbellifera Tops., but besides other characters this latter species has only one form of ancorae. Locality: Station 89, the Denmark Strait, 640 45' L,at. N., 27° 20' L,ong. W., depth 310 fathoms; two specimens. 4. H. tenuisclera n. sp. PL XI, Fig. 7. Incrusting ; surface smooth. Spicula: mcgasclcra ; the skeletal spicules acanthostyli with a small but generally distinct head, somewhat densely spirted in the whole length, 0-083 — o-/p""", not divided into hvo groups; the dermal spicules strongyla o-i$ — o'2i""" ; microsclera small isancorce unguifera with 5 — 8 teeth at each end, 0-016 — cro2o""". This species forms incrustations on Bryozoa (Retepora and Cellepora), on Brachiopods and on tubes of Placostegus tridentatus. Its greatest extent is about I5mm, and it is very thin, not reaching 0-5 nim. The colour (in spirit) is whitish. The surface is smooth or it may be finely hispid from pro- jecting acanthostyli, but this latter condition is certainly due to some damage. The dermal membrane is a thin and transparent film. Oscula and pores were not observed. The skeleton. The dermal skeleton consists of bundles of dermal spicules stretching from the skeleton below to the dermal membrane, the spicules are somewhat penicillately spread outwards; besides these bundles some more irregularly scattered spicules are seen; the bundles and spicules are not at all densely placed, and the dermal skeleton is somewhat weakly developed. The main skeleton is of typical construction, and it is rather regular, consisting of vertical acanthostyli. At the base there is a very small amount of spongin, only observable with difficulty. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli; they are generally straight, only rarely very slightly curved; the head is not large but as a rule distinct, and the shaft tapers evenly from the head to the point. The styli are somewhat densely spined in their whole length, sometimes the spines may be a little more dispersed towards the point; the spines are medium sized and reclined, on the head they are somewhat long, blunt and radiating straight out The styli vary somewhat in length, but they are not divided into groups; the length is 0-083— 0-19 mm and the diameter of the head o-on- 0-024 mm. 2. The dermal spicules are straight and slender strongyla; they are of the same thickness in the whole length and sometimes they are a little polytylote; the ends may be slightly swollen. The length is 0-15— o-2imm and the diameter 0-0028— 0-004 mra. b- Microsclera; these are isancorae anguiferae; they are small and have a slender, curved shaft and five to eight narrow teeth at each end; there may be some irregularity present, the teeth sometimes being of different length and breadth and often the number of the teeth is different at the two ends; there are very narrow alae on the shaft, but they are difficult to observe. The curvature of the shaft is generally very strong, but there is some variation on this point, especially in different individuals. The length of the ancorae, which is somewhat dependent on the curvature, is 0-016— 0-020 mtn, and the diameter of the shaft is about o-ooimm. The ancorae are present in great numbers in the dermal membrane but occur also otherwise in the tissue. This species is very nearly related to //. biscutclla Tops., but it is distinguished by several The Ingolf-Expcdition. VI. 3. l(> I22 PORIFERA. III. characters, the acanthostyli are smaller and the ancorse in biscutclla are described as having ten or about ten teeth ("une dizaine"), and they are larger, 0-027— 0-030 mm; finally the present species does not show the "cellules spheruleuses" mentioned by Tops en t for biscutella. Locality: Station 6, 63° 43' Lat. N., 140 34' Long. W., depth 90 fathoms; station 32, 66° 35' Lat. N., 56° 38' Long. W., depth 318 fathoms; further it has been taken at 630 18' Lat. N., 210 30' Long. W., depth 94 fathoms (The Fishery investigation steamer "Thor"); 6i° 40' Lat. N., 70 40' Long. W., depth 135 fathoms (Ditlevsen); 620 23' Lat. N., 2° 35' Long. E., depth 217 fathoms (Ad. Jensen, the cruise of "M. Sars" 1902). In all six specimens. The localities are situated in the Davis Strait, South and East of Iceland, West of the Faroe Islands and between the latter and Norway. Leptolabis Tops. Lncrusting forms ; external appearance, skeleton and mcgasclcra as in Hymedesmia; the dermal spicules tylota ; the character is tic microsclera are forcipes of one or two forms, to these arc added chela- arcuata and sigmata. Top sent founded this genus in 1904 (Resultats des camp, scient. du Prince de Monaco, Fasc. XXV. 181) and I think he was right, the presence of forcipes being here, as in the genus For- cepia, of sufficient importance for the creating of a genus; moreover the dermal tylota seem to be characteristic for the genus. The genus Leptolabis comprises at present the following species: 1888. Z. liicieusis Tops. Arch, de Zool. exp. et gen. 2. VI, XXXVII, [Deudoryx). 1892. L. exilis Tops. ibid. 2, X, XXII, (Leptosia). 1904. L. forcipula Tops. Resultats des camp, scient. du Prince de Monaco, Fasc. XXV, 182, PI. XV, fig. 11. « L. forcipula var. brunnea Tops. ibid. 182, PI. XV, fig. 12. « L. arcuata Tops. ibid. 183, PI. XV, fig. 18. 1905. L. irritans Thiele, Zool. Jahrbueher, 1905, 455, Taf. 31, Fig. 71a— e [Hymedesmia). L. assimilis mini. I have remarked below, that I consider L. forcipula var. brunnea as a definite and separate species; the same may I think be said with certainty about L. luciensis and exilis ; on reading the description of luciensis of 1904 I got the impression that besides exilis perhaps still a third species may be hidden here. 1. L. assimilis u. sp. PI. XI, Fig. 8. lncrusting ; surface smooth. The main skeleton weak. Spicula : megasclera ; the skeletal spicules acanthostyli divided into two groups, large and small; the large without head, somewhat densely spincd in almost the whole length, 0-42 — 0-53"""; the small zuith a slight head, spined in about the loiver half, o-o8g — o-2/"""; the dermal spicules tylota with small szvcllings, 0-38— 0-50""" ; microsclera four forms ; chela; arena to; 0-014 — 0-038""", sigmata 0-077 — o-/6""", spinulous forcipes of hvo forms, large, with legs of equal length, 0-024 — 0-034""". small, with unequal legs, 0-014 — o-o/8""". PORIFERA. III. 123 This species grows on a large stone together with a Sarcophyton and various sponges of the genera Tedania, Hymcdesmia and Crella. It forms an incrustation of a greatest extent of 30 mm, the thickness being scarcely 0-5 mm. The colour (in spirit) is greyish. The surface is smooth without pro- jecting spicules. The dermal membrane is not especially thin and it is somewhat solid; it is charged with microsclera, especially sigmata, and there are fibres of dermal spicules in it or just below it. Oscnla and pores were not observed. The skeleton. The dermal skeleton consists of bundles and fibres stretching up to the dermal membrane, but in a very horizontal direction, and especially there are fibres running almost or quite horizontally in or just below the membrane; the dermal skeleton is thus chiefly constructed of hori- zontal fibres, and the fibres may reach some length; otherwise they have a more or less irregular course, and they are often curved; they may be of different thickness but are often rather thick, e. g. o-iomm. The main skeleton consists of acanthostyli placed with the heads on the substratum and directed vertically, or generally more or less obliquely upwards; they are much scattered and present only in somewhat small number; the main skeleton is thus diffuse and irregular and on the whole somewhat weakly developed. The acanthostyli are not evenly scattered over the surface of the sub- stratum, but they are to some degree collected in bundles with a few spicules in each. There seems to be a small amount of spongin at the base of the acanthostyli. Spicula: a. Megasclera. 1. The skeletal spicules are acanthostyli which are divided into two groups, large and small; the large styli are straight or a little curved; the basal end is rounded, without any head-swelling or with this only very weakly developed, the other end tapers into a middle-long apex. The styli are somewhat densely spined in almost their whole length, only a short apical part being smooth; the spines are of medium size or small, and they are not reclined but radiating straight out; on the basal part there may sometimes be some stronger spines. The length of the large styli is 0-42— 0-53 mm and the diameter at the base 0-017 — o-024mm. The small styli are straight; they have generally a somewhat distinct but small head, and the point is somewhat short; the spinulation is continued somewhat beyond the middle so that the apical part is smooth. The length is 0-089 — o-2in,m and the diameter at the base o-oio — o-oi4mm. The small acanthostyli are of rather scarce occurrence. 2. The dermal spicules are tylota; they are straight or sometimes slightly curved, the shaft is cylindrical, not thickened in the middle; the ends have small but somewhat distinct swellings; one end is a little thinner than the other and has the swelling more suddenly marked, but this feature is only slightly pronounced and only noticed by close examination. The length of the tylota is 0-38 0-50 ,nm and the diameter of the shaft 00046— 0-007 mm. b. Microsclera are of four forms, chelae arcuata, sigmata and forcipes of two forms. 1. The chelae have an evenly curved shaft, the alas are lobe-shaped, somewhat narrow and deeply incised below, the tooth is elliptical, of the same length as the alae. The chela varies much in size, the length is 0-014 — 0-038 mm and the diameter of the shaft o-ooi— 0-004 ",m. The intermediate sizes are not numerous and hence the chelae give the impression of being divided into two groups. 2. The sigmata are large, of common shape and more or less contorted; they vary somewhat in size, the length is 0-077— o-i6mm, and the thickness is 0-0040 — o-oo8mm. 3. The large forceps is of the ordinary hair-pin-like shape with legs of equal or about equal length; they have a round curve above, and the legs are somewhat divergent; 16* l2. PORIFERA. III. sometimes the legs are curved slightly outwards and then a little more divergent below; these for- cipes have thus a shape about as the large forcipes in Forccpia Topsentii (The Danish Ingolf Exp. VI, 2, 1905, PI. XIX, fig. 4 d). The forcipes are grittily or rugosely spinulous, and the legs are irregularly rounded or somewhat pointed at the apex, without any knob; they are smooth on the inside of the upper curve. The length of the forceps is 0-024 — °'°34 n,n\ and the thickness of the rod is above in the curve 00035 — 0-0056 mm. In single cases the forceps has the legs extraordinarily divergent, so that the angle is obtuse; this feature is thus parallel to what is likewise the case with the forceps in Forccpia Topsentii, (1. c. fig. 4 e). 4. The small forceps has the legs parallel or slightly divergent, and one leg is longer than the other; this longer leg is curved slightly inwards; the legs terminate with a little knob. This forceps recalls thus the forceps in Forccpia Thielei and F. groenlandica (The Danish Ingolf Exp. VI, 2, PI. XIX, fig. 5 d, PL XX, fig. 3d.); it is inconspicuously spinulous. This forceps is very small, the total length from the curvature to the end of the long leg is 0-014— o-oi8mm, and the thickness above in the curve is about 0-0007 mm. Of the microsclera the chelae and sigmata are numerous, they are seen especially in the dermal membrane, but occur also through the whole sponge; the forcipes are not numerous but of somewhat rare occurrence, and they are not seen in the dermal membrane; otherwise it must be remarked, that the small forceps is difficult to detect on account of its very small size, and it is therefore very liable to be overlooked. This species is evidently nearly related to L. forcipula var. brunnca Tops, which I take to be certainly a distinct species, not specifically identical with forcipula; but the present species differs from brunnca with regard to the size of both megasclera and microsclera; thus Top sent gives the size of the chela to 0-033 mm, an(^ ne does not speak of variation in size; the large forceps in brunnca has also a different shape, the legs being more divergent in their outer part; finally the acanthostyli in assimilis have no specially strong spines at the base and have not the spines on the shaft reclined, both these features being found in brunnca. I may also note, that in assimilis I have found no "cel- lules spheruleuses" which are mentioned by Topsent for brunnea. Tops en t mentions, besides the larger forcipes, some small ones of a length of 0-013 mm and very thin, but he does not describe them more particularly; he thinks that they "representent soit la form jeune soit une etat athrophique de cette sort de microscleres". Developmental stages they cannot be, according to what we know about the development of the spicules, the growth taking place only by apposition; there is on the other hand also no reason to believe them to be atrophied forms. It is no doubt a special, small forceps, so that brunnca, like arcuata and the present species, has also two forms of forcipes, large and small. Locality: Station 46, West of the Faroe Islands, 6i°32'Lat.N., n°36'L,ong.W., depth 730 fathoms. One specimen. 't!>3«®i V A .7" Plate V. Plate V. Page Fig. i. Cornulum textile Cart, a strongyla x 200 b the two ends of a distinctly spined strongylum x 700, c chelse arcnatse, front and side view x 1400, d toxa x 340 22 — 2. Grayella pyrula Cart, a tornota, b aeanthostyli x 255, c chelse arcuatse, front and side view x 1000 30 — 3. Grayella gelida n. sp. a tornota, b acanthostrongyla x 255, c chelse arcuatse front and side view x 1000 34 — 4. Grayella carnosa Tops, a tornota, b acanthoxea, c a developmental stage x 255 36 — 5. Hymedesmia Koehleri Tops, a aeanthostyli of various sizes, b polytylote strongyla x 255, c chelse arcuatse, front and side view x 1000. The spicules are from a typical specimen 42 — 6. Hymedesmia laccra n. sp. a aeanthostyli of various sizes, b strongylum x 255, c chela arcuata, side view x 1000 44 — 7. Hymedesmia storca n. sp. a aeanthostyli of various sizes, b strongylum x 255, c chela arcuata, side view x 1000 45 — 8. Hymedesmia lamina n. sp. a aeanthostyli of various sizes, b strongylum x 255, c chelae arcuatse, side and back view x 1000 46 Tin Ingolf-E.xpedilion . I 7. .7. lundbe.ck: I'orH'era 111. PLY. ^ 3* 6" Plate VI. Plate VI. Page Fig. i. Hymedestnia mollis n. sp. a acanthostyli of various sizes, b strougylum x 255, c chelae arcuatae, side view x 1000 47 — 2. Hymedesmia curvichela 11. sp. a acanthostyli of various sizes, b strongylum x 165, c chela arcuata, side view x 1000 48 — 3. Hymedesmia rugosa n. sp. a acanthostyli, large and small, b strongylum x 255, c chelse arcuatas, front and side view x 700 50 — 4. Hymedesmia spleni/im n. sp. a acanthostyli, large and small, b strongylum x 255, c chela arcuata, side view x 1000 51 — 5. Hymedes)nia tenuicula n. sp. a acanthostyli, large and small, b strongyla x 255, c chela arcuata, side view x 1000 52 — 6. Hymedesmia similis n. sp. a acanthostyli, large and small, b strongylum x 255, c chela arcuata, side view x 1000 53 — 7. Hymedesmia nummulus n. sp. a acanthostyli, large and small, b strongylum x 165, e chela arcuata, side view x 1000 55 — 8. Hymedesmia dubia n. sp. a acanthostyli, large and small, b strongylum x 255, c chela arcuata, side view, a little from the front so that the flat front side of the shaft is seen x 1000 56 — 9. Hymedesmia stylata n. sp. a acanthostyli, large and small, b strongylum x 255, c chela arcuata, side view, a little from the front x 1000; when seen accurately in side view, the alae would be more claw-shaped 57 Tin hii/ii/f Expedition IT.-'!. Lundbeck: Porifera 111. /'/. VI. Plate VII. Plate VII. Page Fig. i. Hymedesmia verrucosa n. sp. a acanthostyli of various sizes, b strongylum x 255, c chelae arcuatae, oblique front view and side view x 1000 58 — 2. Hymedesmia procumbcus n. sp. a acanthostyli of various sizes, b tornotum x 255, c chela arcuata, side view x 1000 60 — 3. Hymedesmia perforata n. sp. a acanthostyli of various sizes, b tornotum x 255, c chelae arcuatae of various sizes, side view x 1000 61 — 4. Hymedesmia clavigera n. sp. a acanthostyli, large and small, b tornotum x 255, c chela arcuata, side view x 1000 62 5. Hymedesmia platychela 11. sp. a acanthostyli of various sizes, b tornotum x 255, c chela arcuata, front view x 1000; one tooth is cleft 63 — 6. Hymedesmia basispiuosa n. sp. a acanthostyli, large and small, b tornotum x 255, c chela arcuata, side view x 1000 64 — 7. Hymedesmia lougistylus n. sp. a acanthostyli of various sizes, /; tornotum x 165, c chela arcuata, side view x 1000 66 — 8. Hymedesmia occulta Bow. a acanthostyli, large and small, b one of the tornota, c one of the oxea from the dermal skeleton, d one of the thicker oxea from the dermal mem- brane, e one of the specially thick dermal oxea from the specimen mentioned in the text x 165, f chelae arcuatae, side and front view x 1000 67 — 9. Hymedesmia simillima n. sp. a acanthostyli, large and small, b dermal oxeum, c one of the thick dermal oxea x 165, d chela arcuata, side view x 1000 69 The Ingolf-Exfieditioji VI. 3. Inndbeck: Porifera III. PI. VII. '' \ 8" s' S 8' <>•> V r _, ( o\ ■ — 1 3 Ao ^y Plate VIII. Plate VIII. Page Fig. i. Hymedesmia baculifera Tops, a acanthostyli of various sizes (from a specimen with large styli), b tylotum x 255, c chela arcuata, side view x 1000 71 — 2. Hymedesmia levis n. sp. a acanthostyli of various sizes, b polytylote tylotum x 255, c chela arcuata, side view x 1000 73 — 3. Hymedesmia bractea n. sp. a acanthostyli, large and small, b tylotum x 255, c chela arcuata, side view, a little from in front x 1000. ... 74 — 4. Hymedesmia IcBvistyhis n. sp. a acanthostylus, b tylotum x 255, c chela arcuata, side view, a little from in front x 1000 74 — 5. Hymedesmia Bozverbaiiki n. sp. a acanthostyli, b tylotum x 340, c chela arcuata, side view x 1000 75 — 6. Hymedesmia iruncata n. sp. a acanthostyli, b tylotum x 340, c chela arcuata, side view x 1000 77 — 7. Hyjuedesmia latruiiculioidcs n. sp. a acanthostyli, b tylotum x 340, c chela arcuata, side view, a little from in front x 1000 78 — 8. Hymedesmia irregularis n. sp. a acanthostyli of various sizes, b polytylote dermal stylus x 255, c chelae arcuatse, front and side view x 1000 80 — 9. Hymedesmia proxima n. sp. a acanthostyli, large and small, b dermal stylus x 255, c chelse arciiatae, front and side view x 1000 81 — 10. Hymedesmia crux 0. Schmidt, a acanthostyli of various sizes, b subtornotum x 255, c chelae arcuatse, front view (the spines on the back of the shaft are seen shining through) and side view, d seen from the end x 1000 83 The Ingotf- Expedition VI. ,1. Limdberk: Poriferu III. PI.V11I. ■ :> to lir J / Plate IX. Plate IX. Page Fig. i. Hymedesmia aenigma n. sp. a acanthostyli of various sizes, b tornotum x 255, c— /asteroid chelae in various views, c the axis distinct, with the convex side to the right, d the axis cannot be pointed out, e front view, the axis in the middle, / seen from the end, g a developmental stage x 1000 84 — 2. Hymedesmia filifera O. Schmidt, a acanthostyli of various sizes, b strongylum x 255, c chela arcuata, side view x 1000 86 — 3. Hymedesmia grandis n. sp. a acanthostyli, large and small, b strongylum x 255, c chelae arcuatse, front and side view x 1000, d sigmata of various sizes x 460 88 — 4. Hymedesmia digitata n. sp. a acanthostyli, large and small, b tylotum x 255, c chela arcuata, side view x 1000, d sigmata x 460 90 — 5. Hymedesmia trichoma n. sp. a acanthostyli, large and small, b tylotum x 255, c chela arcuata, side view x 1000, d sigmata x 460 91 — 6. Hymedesmia macrosigma n. sp. a acanthostyli of various sizes, 6 strongylum x 255, c chelae arcuatse of various sizes, side view x 1000, d sigmata, large and small x 340 92 — 7. Hymedesmia pugio n. sp. a acanthostyli, large and small, b dermal stylus x 255, c chela arcuata, side view x 1000, d sigmata x 585 94 — 8. Hymedesmia consanguinea n. sp. a acanthostyli, large and small, b tornotum x 255, c chela arcuata, side view x 1000, d sigmata x 585 95 ■!' I'.xjk dilimi VI. 3. lundbeck: Porifera III. PI. IX. Plate X. Plate X. Page Fig. i. Hymedcsmia planca n. sp. a acanthostyli, large and small, b tylotornotum x 255, c chela; arcuatse of various sizes, front and side view x 1000, d large sigmata, e small, circularly curved sigmata x 585 96 2. Hymedcsmia cultrisigma n. sp. a acanthostyli, large and small, b tylotum x 255, c chela arcuata, side view x 1000, d sigmata of the large, peculiar form, c sigmata of the ordinary form x 585 97 — 3. Hymedcsmia mucronata Tops, a acanthostyli of various sizes, b oxytornota x 255, c chela arcuata, side view, d — c the peculiar chela, d side view, e seen in oblique front view and somewhat from the end, in this view the points of the processes are not seen and the processes appear therefore rounded at the ends x 1000, f sigmata x 585 ... 98 — 4. Hymedesmia tenuisigma n. sp. a acanthostyli, large and small, b polytylote strongylum X 255, c sigmata x 460 100 — 5. Hymedesmia Dujardinii Bow. a acanthostyli of various sizes, the middle one with a slight head-swelling on account of the shaft being thick below, b strongylum and tylotum x 255 101 — 6. Hymedcsmia primitive/, n. sp. a acanthostyli of various sizes, b polytylote strongylum x 255 104 — 7. Hymedesmia longurius n. sp. a acanthostyli of various sizes, b a thinner and a thicker strongylum x 255 105 — 8. Hymedesmia ccqiiata 11. sp. a acanthostyli of various sizes, b strongylum x 255 106 The liiffolf- Expedition 17..'.'. Lmulbeck: Poril'era III. PLY. • r 5 i • ■■ Plate XI. Plate XL Page Fig. i. Hymedesmia dermata n. sp. a acanthostyli, large and small, b strougylum X 255 107 2. Hymedesmia tornotata 11. sp. a acanthostyli of various sizes, b toniota with microspiued ends x 255 I09 — 3. Hymedesmia mucronclla n. sp. a acanthostyli, large and small, b tornotum, the upper end with a mucro x 255 IIQ — 4. Hymenancora interjecta u. sp. a acanthostyli, large and small, b tylotum x 255, c ancorse, front and side view x 1000, d sigmata x 460 «7 — 5. Hymenancora conjungens n. sp. a acanthostyli, large and small, b tylotum with somewhat swollen ends x 255, c ancorse, side view and oblique front view, x 1000, d sigmata x 460 Il8 — 6. Hymenancora duplicata n. sp. a acanthostyli of various sizes, b tornotum x 255, c ancorse spatuliferse of the large form, oblique front view and side view, d ancorse spatuliferse of the small form, front view and side view, the latter shows two smaller teeth at the upper end x 1000 ll9 — 7. Hymenancora tomisclcra 11. sp. a acanthostyli of various sizes, b strongylum x 255, c ancorse unguiferae, side view, with more and less curved shaft x 1000 121 — 8. Leptolabis assimilis n. sp. a acanthostyli, large and small, b tylotum x 255, c chelse arcuatse of various sizes, side view x 1000, d large forcipes x 1000, e small forcipes x 1400, f sigmata x 340 J22 lion 1 7.7. /.on,!/,,, ifh-a 111. Pl.XI. >. . »' INGOLF-EXPEDITIONEN 1895 — 1896. STATIONERNES PLADS, DYBDE OQ BUNDTEMPERATUR. Station Xr. N. Brd. V. Lgd. Dybde i danske Fvn. Bund- tt-inpe- ratur Station Nr. Dybde Bund- N. Brd. ' V. Lgd. i danske tempe- Fvn. ratur Station Nr. Dybde Bund- N. Brd, V. Lgd. i danske tenipe- Fvn. ratur 9 io 12 '3 14 15 16 17 18 19 20 21 22 25 620 30 63° 04' 63° 35' 64° 0/ 64° 40' 63° 43' 63° 13' 63° 56 64° iS' 640 24' 11 J 64° 34' 640 38' 64° 47' 64° 45' 66° iS' 65° 43' 62 ° 49' 61° 44' 60° 29' 5S0 20' 53° 01' 58° 10' 6o° 43' 8° 21' 90 22' 10° 24' ii° 12' 12° 09' 14° 34' 15° 4i' 240 40' 270 00' 280 50' 31° 12' 35° 05 25° 59' 260 58' 260 55' 3°° 29' 34° a' 40° 48' 44° 45' 48° 25' 56° 00' 132 7°2 262 ,0, 5 3 272 o°5 237 2°5 155 90 7°o 60O 4°5 136 6°o 295 5°8 788 3°5 1300 i°6 1040 o°3 622 3°° 176 4°4 33° -o°75 250 6°i 745 3°4 "35 3°o 1566 2°4 1695 i°5 [330 2°4 1845 i°4 km, Ptanktnti- ■ 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 4i 42 43 44 630 06 56° 00' 63° 30- 54° 25' 63 51' 53° 03 6.3° 57' 52° 41' 64° 37' 54° 24' 64° 54' 55° io' 65 ■) 55° 42' 65°34' 54° 31' 66° 50' 54° 28' 66° 35' 55° 54' 66° 35' 56° 38- 67° 57' 55° 30' 65° '7' 54° 1/ 65° i6' 55° 05' 61° 50' 56° 21' 6o° 17' 54° os- 59° 12 Si0 05' 62°oo' 22° 38' 62°oo' 21° 36' 61° 39 17° io' 6i°4i' io° 17' 6i°42 IO° II ' 61° 42' 9° 06' 1 199 582 136 54 109 393 420 6S 22 88 318 35 55 362 1435 1715 1870 865 845 1245 625 645 545 2U4 3°3 o°6 3"5 0°2 i°05 i°6 3°9 o°8 3°6 >°5 i°4 '°3 2°9 3°3 2°0 o°4 o°o5 4°8 45 4b 47 48 49 50 5i 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 6i°32' 9 W' 61° 32' i'° 36' 61° 32' ■5° 4o' 61° 32' 15° 11' 62° 07' 15° 07' 62° 43' 15° 07' 64° 15' 14° 22' 63° 57' 63° IS' 15° 07' 6 15° 4o' 63° 33' 15° 02' 64° 00' 15° 09' 63° 37' 13° 02' 64° 25- 12° 09' 65° 00' 11° 16' 65° 09' 12° 27' 65° 03' 13° °6' 63° 18 19° 12 62° 40' 19° 05' 62° 06' 19° OO' 61 33' 19° OO' 61 33' 20° 43' 6i°30' 22° 30' 645 720 950 1 1 50 II20 I020 6N 420 795 691 3i6 68 35o 211 310 124 55 72 .Six j 1041 1089 II2S 975 4°I7 2°40 3°23 3° 1 7 2°gi 3°i3 7°32 7°87 3°o8 3°9 5°9 7°57 3°4 o°8 ^o°i °°9 o°4 7°92 4°o 3°i 3°° 3°3 3°o Station Xr. N. Brd. \ . Lgd. Dybde i danske Fvn. Bund- tempe- ratur Station Nr. N. Brd. V. Lgd. Dybde i danske Fvn. Bund- tempe- ratur Station Nr. N. Brd. V. Lgd. Dybde i danske Fvn. Bund- tempe- ratur 6S 62° 06' 22° 30' 843 3°4 92 64° 44' 32° 52' 976 l°4 11S 68° 27 8° 20' 1060 — i°o 69 620 40' 22° 17' 5S9 3°9 93 64° 24' 35° 14' 767 i°46 119 67° 53' io° 19' IOIO — i°o 70 63° 09' 22° 05' '34 7°o 94 64° 56' 36° 19' 204 4°. 120 67° 29 11° 32' 885 — i°o 7i 630 46' 22° 03' 46 65°3i' 3°° 45' 213 121 66° 59 13° 1 1' 529 -o°7 72 63° 12' 23° 04' 197 6°7 95 65° 14' 3°° 39 752 2°I 122 66° 42' 14° 44' 115 i°8 73 620 58' 23° 28' 486 5°5 96 65° 24' 29° 00' 735 I°2 123 66° 52' 15° 40' 145 20O 74 620 17' 24° 36' 695 4° 2 97 65° 28' 27° 39' 45o 5°5 124 67° 40' 15° 40' 495 — o°6 61° 57' 25° 35' 76, 98 65° 38' 26° 27' U8 5°9 125 68° 08' 16° 02' 729 — o°8 61° 2S' 25° 06' S29 99 66° 13 20 3o 1S7 6° 1 X26 67° 19' 15° 52' 293 o°5 75 61° 28' 26° 25' 780 4°3 100 66° 23' 14° 02' 59 o°4 127 66° 33' 20° 05' 44 5°6 76 60° 50' 26° 50' S06 4°i IOI 66° 23' 12° 05' 537 — o°7 I2S 66° So' 20° 02' 194 o°6 77 6o° 10' 26° 59 95i 3°6 102 66° 23 IO° 26' 75° — o°9 129 66° 35' 23° 47' "7 6°5 7S 60° 37' 27° 52' 799 4°5 103 66° 23' S° 52' 579 — o°6 130 63° 00' 20° 40' 33S 6°55 79 60° 52' 28° 58' 653 4°4 104 66° 23' 7° 25' 957 — i°i 13. 63° 00' 19° 09' 69S 4° 7 So 61° 02' 29° 32' 935 4°o 105 65° 34' 7° 31' 762 — o°8 132 63° 00 17° 04' 747 4°6 Si 61° 44' 27° 00' 485 6° 1 106 65° 34' 8° 54' 447 — o°6 133 630 14' m° 24' 230 2°2 S2 61° 55 27° 28' 824 4° 1 65° 29' 8°4o' 466 ■34 62° 34' 10° 26' 299 4° 1 •S3 620 25' 28° 30' 912 3°5 107 65° 33' 10° 28' 492 — o°3 135 62° 48' 9°48' 270 o°4 620 36' 26° 01' 472 108 65° 30' 12° 00' 97 i°i 136 63° 01' 9° n' 256 4°S 62° 36' 25° 30' 401 109 65° 29 13° 25' 3S i°5 137 63° 14' 8° 31' 297 — o°6 S4 620 S8' 25° 24' 633 4°8 no 66° 44' n° 33' 781 — o°S 13S 63° 26' 7°56' 47' — o°6 85 63° 21' 25° 21' 170 in 67° 14' 8°48' 860 — o°9 139 63° 36' 7° 30' 702 — o°6 86 65° 03'° 23°47'o 76 112 67° 57' 6° 44' 1267 — I°i 140 63° 29' 6° 57' 780 -o°9 S7 65°02'3 230 56' 2 no "3 69° 3i' 7°o6' 1309 — l°o 141 63° 22' 6° 58' 679 -o°6 88 64° 58' 24° 25' 76 6°9 114 70° 36' 7° 29' 773 — i°o 142 63° 07' 7° 05' 587 -o°6 89 64° 45' 27° 20' 310 8°4 "5 70° 50' 8°29' 86 o°i 143 62° 58' 7° 09' 38S -o°4 90 64° 45' 29° 06' 56S 4°4 116 70° 05' 8° 26' 37i -o°4 144 62° 49' 7° 12' 276 i°6 9' 64° 44' 31° 00' 1236 3°i 117 69° 13' 8°23' 1003 — i°o ->-0— »-<8>*~0-<- THE DANISH INGOLF-EXPEDITION. HITHERTO PUBLISHED: 1899. Vol. I, Part I. 1. Report of the Voyage by C.F. Wandel (1 plate) } 2. Hydrography by Martij)/ R~7iudsen (34 plates) ) 19oo: — Part II. 3. The deposits of the sea-bottom by O. B. Bocggild (7 charts) v 4. Current-bottles by C. F. Wandel (1 plate) 1899. Vol. II, Part I. The ichthyological results by Chr. Liitken (4 plates) . . . ^99. — Part II. On the Appendices genitales (Claspers) in the Greenland- Shark, Sonmiosus microcephalus (Bl. Schn.), and other Sela- chians by Hector F. F.Jungersen (6 plates) 1900. Part III. Nudibranchiate Gasteropoda by R. Bcrgh (5 plates) . . . 1904. Part IV. The North-European and Greenland Lycodinse by Adolf Sever in Jen sen (10 plates) 1899. Vol. Ill, Part I. Pycnogonidee by Fr. Meinert (5 plates) 1908. Part II. Crustacea Malacostraca, I: Decapoda, Euphausiacea, Mysidacea by H.J. Hansen (5 plates) 1903. Vol. IV, Part I. Echinoidea, Part I, by 77/. Mor tense n (21 plates) IO/o7. — Part II. Echinoidea, Part II, by Th. Mortensen (19 plates) 1904. Vol. V, Part I. Pennatulida by Hector F. E.Jungersen (3 plates) 1902. Vol. VI, Part I. Porifera (Part 1), Horaorrhaphidse and Heterorrhaphidae by Will. Lundbeck (19 plates) 1905. Part II. Porifera (Part 2), Desmacidonidse (Pars) by Will. Lundbeck (20 plates) •1910. Part III. Porifera (Part 3), Desmacidonidse (Pars) by Will. Lundbeck (11 plates) Kr. 25,00 (Sh. 30) 8,00 ( - 11) - i3>°° ( " l8) - 4,75 ( " 7) 9-75 ( - 13) 6,00 ( - 9) 8,00 ( - 11) 20,00 ( - 24) 19,00 ( - 23) 6,5° ( - 9) 17,00 ( - 22) 20,50 ( - 25) 12,00 ( - 16)