ECHINODERMA TA—ECHINOIDEA . 



595 



Order SPATANGOIDA Duncan. 

 XXIV. EcHiNOBRissus Brcyn. 

 Test variable, concave beneath. Ambulacra unequal, open at 

 the end of the subpetaloid parts. Pairs of pores in simple series, 

 the outer ones elongate. Below the subpetaloid parts the pores are 

 in small oblique pairs sometimes united by grooves. Peristome 

 anterior to center. Periproct at upper end of a groove situated 

 on the upper surface of the test. Jurassic-Tertiary. 



Fig. 1928. a-c, Echinobrissus texanus, upper, under and side views ; d-g, Cussi- 

 dulusjlorealis, lower, lateral and upper views and enlargement of right postero-lateral 

 ambulacrum. (After Clark.) 



37. E. texanus Clark. (Fig. 1928, a-c.) Cretacic. 



Test ovate, rounded and low anteriorly, subquadrate posteriorly. 

 Ambulacra narrow. Apical disk forward of center. Mouth open- 

 ing small. 



Austin chalk (Niobrara) of Texas. 



XXV. Cassidulus Lamarck. 

 Test small, oblong, depressed convex dorsally, flat below ; ambu- 

 lacra short, subpetaloid, not closing; pores continued from the 

 middle part to the well-developed floscelle; mouth in front of 

 middle; periproct longitudinally elongated, on the upper posterior 

 margin. Cretacic-Eocenic. 



