LAMELLIBEANGHIATA FEOM THE EOCENE MAELS. 231 



ASTARTIDiE. 



Genus ASTAETE Sowerby. 



Astarte castanella, n. sp. 



Plate XXX, Fijrs. 1 and 2. 



Crassina? veta Conrad. Am. Jour. Conch,, Vol. V, p. 41, PI. I, Fig. 5. 

 Not Astarte veta Conrad. Am, Jour. Conch, Vol. IV, p, 279, PI, XX, Fig, 4, or Vol. V, 

 p. 227. 



Mr, Conrad describes this species in the following words: "Triangular, 

 inequilateral, convex; posterior dorsal margin straight and oblique; anterior 

 extremity angular and situated much above the line of the ventral margin, 

 which is crenulated within ; cardinal pit under the apex of the left valve, 

 triangular, wide, oblique. (Cast.) Locality, Shark River, N. J." 



I have seen only casts of this species, and do not think it has been 

 recognized under any other form. Thei-e are two forms associated with each 

 other so nearly alike that it is somewhat difficult to distinguish between 

 them ; yet I believe them to form two distinct species. One of the marked 

 features of this one is its crenulated basal margin, which is the only feature 

 that would enable one to sa)' to which Mr. Conrad's description ap^jlies. 

 The form is more transverse than that of the other, sometimes becoming 

 almost elliptical in outline inside of the imj^ression of the beak and hinge- 

 plate. The posterior end is also more distinctly truncate, with a slight um- 

 bonal angle, and the anterior end somewhat longer proportionally. The 

 margin of the valve is strongly, and for so small a shell almost coarseh' 

 crenulated, while that of the other is smooth. 



This being a true Astarte, and Mr. Conrad having previously described 

 an Astarte veta in Vol. IV, Am. Jour. Conch., p. 279, and Vol. V, p. 227, 

 his specific name veta cannot stand, consequently, from its very close resem- 

 blance to the recent A. castanea, I change it to A. castanella. 



Formation and locality. — In the top layer of the Upper Green Marls 

 (Eocene) at Shark River, Farmingdale, and Squankum, New Jersey. 



