ECHINODERMATA. 293 



cave. Ambulacral areas subpetaloid on the dorsal surface, the 

 posterior pair somewhat longer than the others. Apical disk 

 highly eccentric, situated anterior to the apex. Oral opening 

 small, situated eccentrically towards the anterior margin. Anal 

 opening small, situated low down on the overhanging, slightly 

 truncated posterior margin. 



The dimensions of the type specimen are : length, 26 mm. ; 

 width, 2,2 mm.; height, 15 mm. 



Remarks. — This species is quite distinct from, either C. ovifor- 

 mis or C. pusillus, from both of which species it may be readily 

 separated by the form of the posterior margin and by the position 

 of the anal opening. 



Formation and locality. — Navesink marl, blufJ east of Atlantic 

 Highlands (Clark). 



Geographic distribution. — New Jersey. 



Catopygus sp. undet. 



A poorly preserved specimen of a species of Catopygus from 

 the Tinton beds presents some similarity tO' C. pusillus, but in its 

 imperfect state of preservation it cannot be with certainty as- 

 signed to that species. Some of the most important diagnostic 

 characters are lacking. 



Formation and locality. — Tinton beds. Beers Hill Cut, south 

 of Keyport (129^). 



Genus Cassidulus Lamark. 



Cassidulus aequoreus Morton. 



Plate XII., Figs. 5-12. 



1834. Cassidulus cequoreus Morton, Synop. Org. Rem. Cret. 



Gr. U. S., p. 76, pi. 3, fig. 14- 

 1864. Cassidulus ccquorcus Meek, Check List Inv. Foss. N. A. 



Cret. and Jur., p. 2. 

 1868. Cassidulus aquoreus Conrad, Cook's Geol. N. J., p. 722. 

 1891. Cassidulus aqiioreus Clark, Johns Hopkins Univ. Circ, 



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



