1908.] AFRICAN CALCAREOUS SPONGES. 437 



specimens consist of solid lumps of the anastomosing tubes 

 typical of the genus Glathrina. They are firm to the touch and 

 similar in appearance to C. coriacea as it grows in the Channel 

 Islands. 



The facial rays of the tri- and quadriradiates (text-fig. 82) vary 

 from 60-120/1 long x 12-16 yu thick, the commonest size being 

 llOxlSyu. The apical rays of the quadriradiates are nearly 

 straight, about the same length as the facial rays and about 8 ju 

 thick. 



The spicules are considerably thicker than in Glathi'ina coii- 

 torta var. spinosa (Min.), and agree better with Haeckel's Clathrina 

 darivinii. 



Clathrina contorta var. spinosa. (Text-figs. 83, 84.) 



Clathrina contorta var. spinosa Minchin (6). 



Three specimens of this sponge were dredged in 3 fathoms 

 in Chwaka Bay, Zanzibar. They were pure white when alive and 

 are translucent white in spirits. They are very delicate in texture, 

 and readily fall to pieces. The largest specimen is a solid lump 

 shown twice natural size in text-fig. 83 ; the others appear to 

 be fragments only. They differ considerably in appearance from 

 the specimens of Clathrina darwinii which were collected at the 

 same time. 



Text-fig. 83. 



Clathrina contorta (Min.). X 2. 



The spicules (text-fig.',84) agree fairly well with Minchin's (6) 

 and von Lendenfeld's (7) descriptions of Clathrina contorta var. 

 spinosa. No oxea were found. 



