HTDEOZOA. 



53 



remain ttiroughout the winter, and again, on the 

 return of spring, once more assume the aspect of 

 the primitive Hydra. 



Fig. 8. 



Development of Cordylophoea : — a, gonoptore of Cordylo- 

 jphora lacustris, showing embryoes in its interior ; b, the same 

 more advanced, with embryoes escaping from its ruptured ex- 

 tremity ; c, an embryo, in its free swimming condition ; d, the 

 same embryo, having assumed a pyriform figure ; e, the embryo 

 in its attached condition ; /, primitive polypite, developed there- 

 from ; g, androphore of the same Cordylophora, its contents es- 

 caping under pressure ; h, caudate cells liberated therefrom ; i, 

 spermatozoa. (All magnified.) 



