ECHINODERMA TA—ECHINOIDEA . 



597 



pairs of pores which are best developed toward the center of the 

 upper surface. Posterior ambulacra long and broad, with oblique 

 pores. Peristome transversely oval; periproct oval, beneath the 

 posterior margin ; apical system elongate. Cretacic. 



Fig. 193 1, a-d, Echinocorys ovalis, dorsal, posterior and ventral views, X Viy 

 and enlargement of apical system ; e-hy Cardiaster cincius, dorsal, ventral and lateral 

 views, X %■> ^^^ enlargement of ambulacral plate. (After Clark.) 



40. E. ovalis Clark. (Fig. 1931,0-0?.) Cretacic. 

 Test contracted posteriorly; peristome near anterior margin; 



periproct situated on a slight elevation. 

 Jerseyan (Vincentown) of New Jersey. 



XXVII. HoLASTER Agassiz. 

 Test oval in marginal outline, flat beneath, swollen and high 

 above. Plates large. Anterior ambulacrum in a shallow groove. 

 Mouth opening subanterior, elliptical, broadest transversely. Anal 

 opening situated above the lower posterior margin, oval. Apical 

 system elongate. Comanchic to Tertiary. 



41. H. completus Cragin. Comanchic. 

 Rather small, subcylindrical on a rotund ovate to broadly oval 



base ; sides subvertical btit slightly convex ; summit flattish-convex ; 

 unpaired ambulacrum about as conspicuous as the others ; madre- 

 poric function shared by four genital plates. 

 Washita of Texas. 



