THALASSICOLLID^ 



45 



The cellseform bodies are often surrounded 

 by peculiar cylindrical spicula, terminating at 

 both extremities in three or four conical rays, 

 beset on either side with minute spine-like pro- 

 cesses. 



Fig. 9, 



Structure of Thalassicollid;e : — a, Sphcerozoum pimctafum 

 (nat. size) ; b, variety of the same ; c, ThalassicoUa nucleata ; 

 d. CoUosphcera Huxhy'i; e, portion of a (magnified), showing 

 two of the celloeform bodies with their coloured vesicles, nuclei, 

 and spicula. 



In some specimens the central cavity is re- 

 placed by an aggregation of large vacuolar 

 spaces (6). 



ThalassicoUa proper is more constant in form 

 than the preceding, and is destitute of cellaeform 

 bodies (c). It contains, however, the coloured vesi- 

 cles above referred to ; these, associated ^vith vacu- 

 olar spaces and very many minute dark gi-anules. 



