292 CRETACEOUS PALEONTOLOGY. 



Catopygus pusillus Clark. 

 Plate XI., Figs. 16-19. 



1891. Catopygus pusillus Clark, Johns Hopkins Univ. Circ., 



vol. 10, No. 87, p. 76. 

 1893. Catopygus pusillus Clark, Johns Hopkins Univ. Circ., 



vol. 12, No. 103, p. 52. 

 1893. Catopygus pusillus Clark, Bull. U. S. G. $., No. 97, p. 



65, pi. 27, figs. 3 a-d. 



Description. Test ovate to subquadrate, rounded in front and 

 subtruncate behind, greatest width back of the middle, ventral 

 surface concave, dorsal surface convex and somewhat elevated. 

 Ambulacral areas narrowly lanceolate, subpetaloid on the dorsal 

 surface, the posterior pair only slightly longer than the anterior. 

 Interambulacral areas wide, composed of large plates. Apical disk 

 small, nearly central. Oral opening small, situated eccentrically 

 in front of the center of the ventral side. Anal opening oval, 

 situated in a nearly vertical anal sulcus, its upper extremity over- 

 hung by a projecting arch. 



The dimensions of a complete individual are : length, 15.6 mm. ; 

 width, 14 mm. ; height, 6.5 mm. 



Remarks. This species has only been observed in the form 

 of internal casts, so that the surface markings cannot be described, 

 but they are, doubtless, similar to those of C. oviformis. The 

 species can be distinguished from C. oviformis by its broader and 

 slightly subquadrate form, its less rounded sides and the more 

 nearly central position of the apical disk. 



Formation and locality. Merchantville clay-marl, near Mata- 

 wan (101). 



Geographic distribution. New Jersey. 



Catopygus williamsi n. sp. Clark. 

 Plate XII, Fig. 1-4. 



Description. Test ovate, slightly broader posteriorly, the 

 posterior margin but little truncated ; dorsal surface rounded and 

 somewhat elevated, but not highly inflated ; ventral surface con- 



