150 



McMURRICH. 



[Vol. V. 



the stage with four mesenteries seems to mark an epoch, much 

 less distinct, however, than that indicated at the close of the 

 Edwardsia stage. 



m 



Oractii 



Hexactinia?. 



Fig. IV. 



Peaciua. 



Starting, however, with the Edwardsia stage, we find it re- 

 peated in the ontogeny of the Ceriantheae, the Zoantheae, and 



