HYALONEMA (HYALONEMA) POLYCAULUM. 201 
slender-rayed basal spicules are about twice as large, and the microhexactines 
are smaller, and composed of more strongly curved rays in the former than in 
the latter; the large macramphidises of H. (H.) obtusum reach 356 yu in length, 
have shafts bearing large spines along their whole length and possess anchors 
the end-parts of whose teeth are parallel to the shaft; the large amphidises of H. 
(H.) agassizi are not over 310 » long, have shafts destitute of large spines outside 
the centre, and possess anchors the end-parts of whose teeth diverge; the end- 
parts of the anchor-teeth of the large micramphidises are in the former far more 
curved than in the latter. 
Hyalonema (Hyalonema) polycaulum is in outer appearance, apart from its 
polycaule nature, similar to the forms described as C, D, and E. It differs from 
this species, however, by its large macramphidises, its pinules, and its mode of 
attachment to the sea-bottom. The large macramphidises are in the sponges 
described above considerably shorter, have relatively narrower anchors and 
anchor-teeth much more strongly curved in their distal part and less divergent, 
than in Hyalonema (Hyalonema) polycaulum. The distal rays of the pinules 
of the former are considerably thickened above the middle and have a stout 
terminal cone. In those of the latter such a thickening above the middle is 
either absent or very insignificant, and the terminal cone is much more slender. 
It is also to be noted that the distal rays of the pinules of the sponges described 
above bear more numerous spines than those of Hyalonema (Hyalonema) poly- 
caulum. The former is attached by a single stalk; the latter by several stalks. 
Hyalonema (Hyalonema) polycaulum, sp. nov. 
Plate 538, figs. 1-17; Plate 54, figs. 1-45. 
One specimen of this species was trawled in the eastern part of the Tropical 
Pacific at Station 4721 on 15 January, 1905; 8° 7.5’S., 104° 10.5’ W.; depth 
3811 m. (2084 f.); bottom composed of light brown Globigerina ooze. It appears 
to have possessed four distinct stalks. To this the specific name refers. 
Shape and size. The single, somewhat fragmentary specimen (Plate 53, 
fig. 4) is oval, 54 mm. long, 48 mm. broad, and somewhat flattened. Only slight 
remnants of the dermal membrane are left, the specimen appearing very porous 
in consequence. A group of large cavities, separated by thin plates, occupies 
one of the flat faces. A thickening at the joining line of these plates, which, 
however, does not project freely, is, as its internal structure shows, a gastral cone. 
The large cavities around it are parts (diverticula) of the gastral cavity. On the 
