ECHINODERMATA—ECHINOIDEA. 603 



oval, large, high up on posterior border, with subanal fasciole; 

 mouth excentric in front; tubercles small. Eocenic-Recent. 



52. E. orthonotum Conrad. (Fig. 1937, ^,/.) Miocenic. 



Ovate, truncate at each end, higher in front; anterior paired 

 ambulacra triangular, posterior narrow. 



Chesapeakean of Virginia and Maryland. 



