450 



ON AFRICAN CALCAREOUS SPONGES, 



[May 12. 



sizes- there is no anastomosis between the branches (see text- 

 fi? 98) The tubes, as preserved, are flattened so that the 

 ^p^po'iVe sides touch ; 'they l.vj inside from 1-3 mm w^e ^he 

 external surface is smooth ; the internal^ surface is lined with 

 quadriradiates with the apical rays projecting inwards. 



Text-fig. 99. 



Grantessa zanzilaris, skeleton of body-wall. X 200. 



The structure of the body- wall is shown in text-fig. 99. The 

 opposite rays of the subdermal and subgastral triradiates lie 

 beside each other, forming a typical non-articulated skeleton ; 

 in addition there are two or three intermediate rows of tri- 

 radiates, apparently the remains of an articulated skeleton. The 

 structure agrees closely with that of Grantessa intusarticulata 

 described and figured by Dendy (3). 



