PORIFERA. I. 



23 



detenniiie the species with certainty; without a comparison with an original specimen an identifying 

 would have been impossible, as the descriptions, as well with regard to this species as to the other 

 species established by Armauer Hansen, are exceedingly short, and the figures of the spicules very 

 incorrect and not to be recognised. 



Locality. From stations 53, 95, and 96 we have some rather well preserved specimens; from 

 stations 21, 27, 28, 104, 106, and 128 we have only fragments, and from the three stations last men- 

 tioned these fragments are so small and damaged, that the only point of support for the determination 

 is the spicules, which, however, agree completely with those of the other specimens. The depths on 

 which the specimens have been taken, vary between 393 and 1330 fathoms; the whole specimens are 

 from a depth of ca. 700 fathoms. The above mentioned stations are situated: in the Davis Strait (27 

 and 28), south of Greenland (21), in the Denmark Strait (95 and 96), north of Iceland (128), and east of 

 Iceland (53, 104, 106). 



Geogr. distr. The species has been taken, besides by the Ingolf-expedition, at the northern 

 coast of Norway, depth 271 metres (The Norwegian North-Atlantic Expedition). 



5. H. osculum n. sp. 

 PI. Ill, Fig.s. 3-7. PI. IX, Figs. 7-9. 

 The /ortn somewhat varying, but a/ways erect and more or less compressed. The surface rather 

 smooth. The dermal membrane Ti'ith an irregular, large-meshed net of spicules. Only one osculum is 

 found, formed like a spout; it may be found near the top or more or less Jar dozvn the side, and 

 sometimes on a special projection. The skeleton consists of an irregular netiuork of loose fibres and 

 here and there spread needles. Spicula oxea o-6 — o-p2'""'. 



This sponge has an erect, more or less compressed form, which ma\' however be somewhat 

 varying. The height of the specimens in hand is about 35'"™. The colour (in spirit) is light brown- 

 gray or yellowish gray. The surface is smooth, but on account of the dermal skeleton it has a 

 wrinkled or coarsel}- reticular appearance. The dermal membrane may as a thin, transparent mem- 

 brane be separated from the tissue below, and is provided with an irregular net of spicules with com- 

 paratively large meshes. With regard to oscula this species is rather interesting, each specimen having 

 only one osculum, which may be situated in a somewhat different way, close to the sunnnit of the 

 sponge or farther down the side, and sometimes it is found on a special projection, which is in one 

 specimen a side-branch'). This osculum has a form about as a conical spout formed by the dermal 

 membrane, and the dermal needles are here arranged in a parallel way with one end towards the 

 oscular opening; from here the}- radiate into the .skin, and pass b\- degrees into the dermal reticula- 

 tion. Sometimes the osculum is only found with difficulty, as it is situated in a depression. The 

 oscular opening leads into a kind of oscular tube, stretching as a hollow through the whole sponge 

 or the greater part of it; in this hollow the openings of the canals are found; the}- are round or oval, 

 and have a diameter of ca. o-i — 1-5""". Round these openings the spicules of the membrane covering 

 the hollow, are grouped as a coarse network. The inner hollow is often for a longer or shorter way 



') 111 this .specimen (PI. Ill, fig. 6), the upper end i.s somewhat damaged; here there might perhaps have been an 

 osculum. 



