282 



biane of the base readily tears into fine fibres; it is densely 

 crowded with stellate spicula of about a fourth the size of those 

 of the sarcode, their radii being very short. 



The dermal membrane of the stem is very thin but similar 

 in structure. The axis of the stem is formed by a direct 

 continuation of the large spicula of the basal part of the 

 sponge immediately beneath the origin of the stem ; they are 

 arranged in a similar manner with their long pointed shafts 

 directed downwards, their triradiate distal extremities assum- 

 ing an asymmetrical character, one of the three terminal 

 radii of each spiculum being greatly prolonged to form with 

 other similar prolongations derived from its neighbouring 

 spicula a flattened band which supports the dermal membrane. 



The principal interest attached to this sponge is, that it 

 consists of two parts extremely different in external appear- 

 ance, and also in the aspect which they present on section, 

 the spicula, however, being of the same type throughout the 

 entire sponge, and only slightly altered to perform a special 

 purpose. 



I have been unable to detect either poi-es or oscula, pro- 

 bably owing to their rapid closure on removal of the sponge 

 from the water. 



