64 CRETACEOUS GROUP 



Pectunculus. 



1. P. hamula, (S. G. M.) PL xv, fig. 7. 



Specific character. Subglobose, smooth and ponderous ; 

 posterior extremity angulated. • 



Diameter, from three-fourths of an inch to an inch. 



Found by Mr. Conrad in the older cretaceous strata at 

 Prairie Bluff, Alabama. 



2. P. australisy (S. G. M.) 



Specific character. Suborbicular, nearly equilateral, convex ; 

 beaks small, pointed, slightly prominent, central ; inner mar- 

 gin crenulated. 



Found with the preceding, from which it differs in be- 

 ing somewhat of a lenticular form ; it is about the same 

 size. It came too late to be figured. 



3. I possess casts of another species from the marl of 

 New Jersey. 



Arca. 



A. rostellata, (S. G. M.) PL iii, fig. 11. 



Specific character. Elongated, narrow, ventricose ; with nu- 

 merous delicate costae radiating from the beaks to the margin; 

 the latter having a subcentral, gaping constriction. 



Length, an inch and a quarter ; breadth, five-eighths of an 

 inch. 



From Alabama. 



CuCULLJEA. 



1. C. vulgaris, (S. G. M.) PL iii, f\^. 8 : and a cast, 

 pi. xiii, fig. 5. 



Specific character. Ventricose, ovato-triangular, flattened 



