ECHINODERMA TA—ECHINOIDEA . 



599 



XXX. Enallaster d'Orbigny. 

 Test heart-shaped, longer than broad, with an anterior groove. 

 Petaloid parts of the anterolateral ambulacra divergent, flexuous, 

 tending to close, and with very unequal pore-bearing zones of 

 which the posterior are the larger. Pairs of pores oblique. Pos- 

 terolateral ambulacra short, divergent. Mouth opening wide, with 

 lip. Anal opening in truncated posterior surface. Comanchic. 



45. E. texanus (Roemer). (Toxaster texanus.) (Fig. 1933, d-^.) 



Comanchic. 



Test broad in anterior portion. Anterior groove deep. Upper 

 surface convex, elevated. Base flat, depressed at mouth opening. 

 Ambulacra narrow, unequal, the posterolateral pair much shorter 

 than the others. Anal opening high on the posterior margin. 



Characteristic of Comanche Peak (Fredericksburg) of Texas. 



XXXI. Hemiaster Desor. 

 Test heart-shaped, longer than broad, depressed, with numerous 

 plates and an anterior groove. The two posterior ambulacra meet 

 close together and are separated from the three anterior by a 



Fig. 1933. a-c, Epiaster whitei, upper, lower and lateral views, X % \ ^-^> 

 Enallaster texanus, upper, lower, lateral and posterior views, X %• (After 

 Clark. ) 



wide space. The anterior ambulacrum lies in a shallow groove; 

 pores oblique and in pairs on either side. The anterolateral ambu- 

 lacra diverge, are dorsally sunken, petaloid, and much longer than 

 the posterolateral. Pores of the petaloid portion united, the outer 

 ones usually the largest. A fasciole present near the edge of the 

 test, surrounding the petaloid parts. Cretacic-Recent. 



