94 



HTDROZOA. 



ported on the curiously modified gonoblastidia, 

 whose structure has previously been described. 

 Among the Campanulariadce they frequently 

 assume the form of free-swimming medusoids; 



Fiff. 19. 



Morphology of Canpanxjlaeiadje : —a, Laomedea neglecta ; b, 

 portion of the same; c, gonoblastidium of Camiyanularia voliobi- 

 lis ; d, gonoblastidium of C. Jolmstoni ; e, gonoblastidium of 

 C. syringa ; f, the same in an earlier stage ; g, upper portion of 

 c, slightly compressed. (All, except a, magnified.) 



but in the Sertulariadoi seldom, if ever, become 

 detached. 



In some Plumularioi the gonophores appear to 

 be naked. In P. cristata the branch bearing 

 these o-rgans undergoes a" curious metamorphosis 



