chap, in.] THE CRUISES OF THE 'PORCUPINE: 1 13 



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, aud full 

 of the bihamate ' spicules of the sarcode ' so charac- 

 teristic of the genus Esperia and its allies. The 

 crust is covered with pores, and rises here and there 

 into papillae perforated by large oscula. This sponge 

 appears to belong to a group allied to the Espe- 

 riadse, 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 (Pig. 13) is very abundant 

 and of a large size. This form was admirably described 

 by Professor Loven — unaccountably under the name 

 of Hyalonema boreale. It is certainly very far from 

 Hyalonema. It is more nearly allied to Tethya, for 

 the body of the sponge must certainly be referred to 



i 



