CHAP. ITt. | THE CRUISES OF THE ‘ PORCUPINE, Pus 
bush or shrub, which appears to clothe the bottom 
in some places over a large area like heather on a 
moor. There are at least three species. In one the 
branches are strict and rigid; while in another the 
arrangement is more lax, side branches coming off 
from a flexible central rachis like the barbs from the 
shaft of an ostrich feather. The branches seem in 
some cases to be from 50 to 80 centimetres in height, 
and the stems near the base are 2 to 3 centimetres in 
diameter. The stem and branches consist of a firm 
central axis, semi-transparent and of a _ peculiar 
yellowish green colour ; composed of a continuous 
horny substance filled with masses of needle-shaped 
spicules arranged longitudinally in dense sheaves. 
This axis is overlaid by a soft bark of sponge sub- 
stance supported by needle-shaped spicules, and full 
of the bihamate ‘ spicules of the sarcode’ so charac- 
teristic of the genus Hsperia and its allies. The 
crust is covered with pores, and rises here and there 
into papillee perforated by large oscula. ‘This sponge 
appears to belong to a group allied to the Espe- 
riade, and perhaps even more closely allied to 
some of the fossil branching forms whose remains 
are so abundant in some beds of the cretaceous 
period. A still finer species of the same group 
was dredged by Mr. Gwyn Jeffreys in the first 
cruise of the following year. 
Another peculiar sponge (Fig. 13) is very abundant 
and of a large size. This form was admirably described 
by Professor Lovén—unaccountably under the name 
of Hyalonema boreale. It is certainly very far from 
Hyatonema. It is more nearly allied to Tethya, for 
the body of the sponge must certainly be referred to 
I 
