HTDROZOA. 91 



uous species. Examples of this habit are afforded 



Fig. 1 8. 



Morphology of Sertulariad^ : — a, dried hydrosoma of Serhi- 

 laria tricuspidata ; b, portion of the same ; c, fragment of the 

 coenosarc from a dead specimen of Halecium halecinum ; d, gono- 

 blastidium of H. Beanii ; e, three gonohlastidia of Sertularia 

 argentea ; — tt', hydrotheca ; k, coenosarc ; p, gonoblastidium. 

 (All, except a, magnified.) 



by the genera Coppinia and Reticularia, and by 

 several of the true Sertularice. 



