PORIFERA. II. 



17 



tapering. The size of the styli is rather varying, the length thus from 0-36 to o - 94 mm , and the thick- 

 ness in proportion from o - oi2 to o-024 mm ; the smaller ones are the least frequent. Developmental forms 

 occur in small numbers down to quite fine ones ; as the fullgrown needles they are of varying length. 

 b. Microsclera; these are only of one kind, isochelse palmatse; they are of the common structure, the 

 shaft is slightly curved, but with a straight middle part, and this free middle part is about one third 

 of the length of the chela. The tooth is somewhat narrower than the alse taken together. When the 

 chela is viewed from the side the recurved lateral edges of the tooth and the alas are only to be seen 

 with difficulty, and only under very high magnifying powers. These chelse are very small, their length 

 is 0-014 — o - oi5 mm , and the breadth is o - oo3 mm ; sometimes they are a little twisted. They are found 

 copiously throughout the sponge and also in the dermal membrane. 



This species is closelv allied to the E. columnata established by Tops en t in 1892 (Resultats 

 des Campagn. scient. du Prince de Monaco, Fasc. II, 90, PI. V, fig. 5, PI. X, fig. 5); it is of a similar form, 

 and also the skeletal structure may be taken to be the same. Further they agree with regard to the 

 size of the spicules and in the fact that the styli are comparatively large, while the chelse are very 

 small, as also in that of the styli being of the same form. Top sent states the measures of the styli 

 to be 075 m " 1 with a thickness of o-oi6 m,n , and the length of the chelse to o•OI6 m,,, . On the other hand 

 there is a difference in the structure of the chelse they being in E. columnata, to judge from the figure, 

 considerably broader, as well when seen from the front as in profile. A measuring of the figure of 

 Top sent gives as the greatest breadth, when seen from the front, o-oo9' nm . 



Locality: Only one specimen from the Davis Strait, station 27, 64 c 54' Lat. N., 55 10' Long. W., 

 depth 393 fathoms. 



5. E. forcipula n. sp. 

 PI. I, Fig. 5. PI. VIII, Fig. 5 a— i. 



(Formed as a thick leaf?) The surface smooth, the dermal membrane provided with spicules, on 

 the pore side forming a network, but otherwise placed irregularly. Oscula scattered. The skeleton con- 

 sists of polysplenia r fibres branching up through the sponge, between them an irregular nehvork. Spicula : 

 Megasclera styli 0-54 — o-68"""; microsclera of four forms, isochehc pal mater (you — o-o/8'" m , isochelcr ar- 

 cuatce 0-038 — <ro5""",- sigmata o'oj — 0-08$"'"; forcipes o-oij""". 



Of this species we have only a couple of fragments, the largest of which has an extent in 

 breadth of 40""" and a height of ca. 30 m,r ; the fragments would indicate that they have belonged to a 

 sponge that has been erect and formed as a thick leaf, perhaps about as E. villosa, and in this case 

 the fragments among other things show the upper part of the sponge. The colour (in spirit) is 

 whitish yellow. The consistency is rather firm. The surface is somewhat wrinkled and folded, but 

 otherwise smooth. The dermal membrane is thin, and on one side of the sponge where no pores are 

 found, it is provided with spicules rather close-set, irregularly scattered, but parallel to the surface. 

 On the other side of the sponge where numerous pores are found, the needles, on the other hand, 

 are arranged as an irregular, polyspicular network round the pores. Oscula are simple, oval, or some- 

 what irregular openings of varying size in the dermal membrane. The spicules of the dermal mem- 

 brane surround the oscular aperture, being arranged in a ring-like way round it, but at some distance 



The Ingolf-Expedition. VI. 2. 3 



