LAMELLIBRANCHIATA OF THE LOWEE MARLS. 131 



forbids its reference to the genus JDosinia. I can find no described species 

 answering to its characters, and have therefore considered it as new. 



Formation and locality. — The character of the cast would indicate that 

 it had been derived from the Lower Marls, and probably from Freehold, 

 although there is no evidence further than its character by which to 

 locate it. 



CHAMID^. 



Genus DIOERAS Lam. 



Diceras dactyloldes, n. sp. 

 Plate XVIII, Figs. 26 and 27. 



A cast of a single valve of what appears to be without question a Dice- 

 ras occurs in the collection. It is rather slender in its proportions, and 

 makes nearly two-thirds of a volution in its curvature, and is apparently a 

 cas't of a left valve, judging from the curvature of the beak. The muscu- 

 lar scar is very large, and has been deeply impressed in the shell, as the 

 scar is considerably raised on the cast and is nearly half as long as the cast 

 itself. On its front margin there is the filling of a deep groove, which is 

 longitudinally marked with lamellose strise, from the edges of the shell 

 lamellae; and on the opposite side of the cast occurs a flattened surface from 

 the thickening of the shell below the hinge-tooth, probably. 



The striations on the filling of the groove bordering the muscular im- 

 print would lead one to suspect the cast might be of a valve of Caprina, 

 but their lamellose character somewhat denies this reference, and the gen- 

 eral character of the specimen would rather indicate a Diceras, The speci- 

 men is quite obscure, besides being the only one known, and consequently 

 affords almost no means of comparison with previously described species. 

 It, however, appears much more slender in its proportions than the species 

 known from Texas and other southern localities, as well as more strongly 

 enrolled. 



Formation and locality, — In the Lower Green Marls, at Bruere's pits 

 near Walnford, on Crosswicks Creek, Monmouth County, New Jersey. 



