168 PALEONTOLOGY OP NEW JERSEY, 



The general expression of this shell when viewed externally is Mactra- 

 like, and, were it not for a knowledge of the hinge, might readily be 

 supposed to belong to that genus; but internally the hinge differs very 

 materially. Dr. Stoliczka, in copying Mr. Conrad's generic description, 

 very properly corrects the V-shaped tooth of the left valve to an /\-shape, 

 and places the genus under the Tellinidai, where it probably belongs, not- 

 withstanding its MadraAike appearance, as it does not possess an internal 

 cartilage plate. 



Formation and locality. — In the micaceous clays of the Lower Marls at 

 Haddonfield, New Jersey. Borrowed from the ^collection of the Academy 

 of Natural Sciences, Philadelphia. 



Genus ENONA Courad, 1871. 



(Am. Jour. Coucli., Vol. VI, p. 74.) 



^iiona Eufauleusis. 



Plate XXIII, Figs. 2 and 3. 



TelUna EufauUnsis Courad. J. A. N. Sci., Vol. IV. p. 277, PI. XLVI, Fig. 15. Gabb, 



Syuopsis, p. 173. Meek, Checklist, p. 14. 

 ^nona Eufaulensis Con. Am. Jour. Concb., Vol. VI, p. 74, Stoliczka, Pal. Indica, p. 482. 



Shell small, triangularly ovate in outline, three-fourths as high as long, 

 with the small beaks situated a little more than one-third of the length from 

 the anterior end. Cardinal margins rapidly sloping from the beaks, the 

 anterior most rapidly, and the anterior end sliarpl}^ rounding just above the 

 basal line; posterior end more broadly rounded, but still narrowed; basal 

 line broadly curved. Surface of the valve smooth and semipolished, the 

 disk rather highly convex for a Tellina-\\ke shell, with very small pointed 

 beaks, a slight angularity of the umbonal region just in front of it, and a 

 very narrow but distinctly circumscribed lunule. In the interior the hinge- 

 plate is very narrow, with a single small cardinal tooth in the right valve 

 and very small and narrow lateral teeth. Muscular markings unknown. 



This species differs from ^nona papyria Conrad, principally in the 

 even, smooth, or semi-polished surface, that one being without polish and 

 marked with uneven concentric lines of comparatively great strength; also 



