230 PALEONTOLOGY OF NEW JERSEY. 



more regular curve to the basal line. This species throws a little more light 

 on the characters of this genus than was known from the Cretaceous spe- 

 cies, as in the example figured on the plate, the entire hinge features can 

 be made out. These show that it is so very closely related to Nuculana as 

 herein used that it becomes a question if Nucularia should be retained as a 

 distinct genus. It is possible there maj^ be some more distinctive feature in 

 the arrangement of the muscles, or in the form of the pallial line, as these 

 features are not observable on the specimens; but so far as the characters of 

 the hinge-plate can be relied upon, I should not consider it a valid genus. 



Formation and locality. — In the upper layers of the Upper Marls, at 

 Shark River, New Jersey. 



Genus AXINEA Poll. 



Azinea Conradi, u. sp. 



Plate XXIX, Figs. 10 aud 11. 



Shell small, the internal cast measuring a little less than one inch in 

 height, and is a trifle narrower than high. Valve depressed-convex, most 

 strongly convex above the middle, and gradually sloping below. Outline 

 nearly circular, equilateral, and slightly pointed at the beak in the cast, but 

 the outline of the hinge-plate would give a more circular form. Hinge- 

 plate narrow, marked on the anterior side by about eight short oblique teeth; 

 opposite side unknown. Muscular scars rather small. Exfoliated surface 

 marked by moderately fine, distinct, rounded striae. The margin denticu- 

 lated to correspond. 



The species differs from A. Mortoni Conrad, from the Lower IMarls, in 

 being less convex, and in being most convex above the middle, whereas that 

 one is evenly rounded. It also differs in being higher than wide, that one 

 being the opposite, and in being more finely denticulate on the margin of 

 the cast. These differences I deem quite specific in forms of this genus. 



Formation and locality. — In the upper, stony layers of the U^^per Marl 

 Bed, at Shark River, New Jersey. 



