LAMELLIBEANCHIATA FKOM THE EOCENE MAELS. 223 



nearly twice the length of that here figured, and presents the features 

 indicated on this cast, but intensified ; the ribs being strong and rounded, 

 and the alation of the hinge well marked ; the curving of the shell toward 

 the front is also very marked. I cannot find that the Claiborne shell has 

 ever been described or indicated by name. It may have been confounded 

 with the young of 0. sellceformis Conrad, to which it bears considerable re- 

 semblance, but that species in its young state, and even in its more advanced 

 stages, never has the lateral curvature nor the strong ribs; although the 

 hinge alation is quite strongly marked and the surface ribbed. The ribs, 

 however, are much finer and the shell proportionally broader and shal- 

 lower. The species diflPers from all other oysters of the Eocene to which I 

 can find reference in the curving shell, combined with the alation of the hinge. 

 Formation and locality. — In the upper bed of the Upper Green Marls 

 at Shark River, New Jersey. 



Ostrea ( Alectrionia ? ) linguafelis, n. sp. 

 iPlate XXIX, Fig. 1. 



This single cast of the lower valve of an oyster-like shell is figured from 

 the Eocene marls. At first I was inclined to refer it to 0. larva Lam., but 

 on close observation I find that it possesses characters which are incompati- 

 ble with that species, and which make it necessary to distinguish it by a 

 distinct name, although from the poor material in hand I was disinclined 

 to do so. 



The form is very obliquely elongate-oval, with a comparatively long 

 cardinal line, apparently auriculate on one side, which, although imperfect, 

 seems to have been extended in the form of a wing. Body of the valve 

 convex, and the surface, as shown on the margin of the cast, mafked by 

 comparatively small radiating plicsp-. Cardinal area small and the liga- 

 mental area narrow and obscure. Muscular scar rather small, and situated 

 above the middle of the shell's length. 



Formation and locality, — In the upper layers of Green Marl at Shark 

 River, New Jersey. Collection at Rutgers College. 



