NO. 4 ECHINOIDS, TRINIDAD AND VENEZUELA — COOKE 7 



face concave around the peristome; margin rounded. Apical system 

 monobasal, slightly anterior, four genital pores; madreporite star 

 shaped, central. Petals alike, extending nearly to the margin ; porifer- 

 ous zones very slightly arched, separated at the distal ends ; inner pores 

 circular, outer pores elongated, pores conjugate; interporiferous zones 

 wider than the poriferous. Peristome defective; slightly anterior, 

 more nearly central than the apical system, Periproct supramarginal, 

 about one-third the way from the posterior margin to the apical sys- 

 tem, twice as long as wide, flush, at the upper end of a shallow depres- 

 sion that indents the margin. Tubercles scrobiculate, more numerous 

 and larger on the lower surface than elsewhere. 



Length 46 mm. ; width 42 mm. ; height 18 mm. 



Occurrence. — Venezuela : Roas Island, Zulia. 



Geologic horizon. — Early Cretaceous : Apon formation, of Aptian 

 age. 



Holotype.—US^yi 131 167. 



Comparisons. — The holotype, a unique specimen, is nearly twice 

 as long and wide but proportionately lower than Phyllobrissus gresslyi 

 (Agassiz), the type species of the genus, as figured by Orbigny (1854- 

 1860, p. 425, pi. 966, figs. 1-6) under the genus Clypeopygiis but 

 referred to Phyllobrissus by Cotteau (Orbigny, 1854-1860, p. 553). 

 The periproct is proportionately longer and narrower, and it is farther 

 forward. 



ENALLASTER (WASHITASTER) BRAVOENSIS Bose 

 PI. I, figs. 1-4 



Enallaster bravoensis Bose, 1910, Inst. Geo!. Mexico Bol. 25, p. 168, pi. 41, figs. 



5-10; pi. 42, figs. 2-12; pi. 43, figs. 1-2, 6-7. 

 Enallaster {W ashitaster) bravoensis Bose. Cooke, 1955, U. S. Geol. Surv. Prof. 



Pap. 264-E, p. 106, pi. 27, figs. 5-12. Includes additional synonymy. 



The single Enallaster here tentatively referred to E. bravoensis 

 has the shape and lies within the size range of that species. It retains 

 traces of a broad granular band surrounding the petals, on which band 

 can be detected obscure narrow streaks of granules or fascioles like 

 those characterizing Washitaster. 



Occurrence. — Venezuela: Rio Socuy, Zulia (Creole Petroleum Co. 

 50878). 



Geologic horizon. — Early Cretaceous : Cogollo limestone, probably 

 of late Albian age. The type of Enallaster bravoensis came from 

 Cerro Muleros in Mexico near El Paso, Tex., and the species is 

 abundant in the Ranchcria Valley of Colombia (Cooke, 1955). In 



