LAMELLIBEANCHIATA OF THE LOWEE MAELS. 151 



The hinge-plate is characterized by two cardinal teeth, widely divergent, 

 with a deep triangular pit between, and the posterior tooth grooved on its 

 surface, a short anterior pit and a long lateral groove behind, which is ver- 

 tically crenulate on the sides. 



The species differs from any other of the genus in its transverse form, 

 small beaks, and less ventricose valves. I find the specimens labeled VenUia 

 subovalis Conrad, in Mr. Conrad's own handwriting, but have not been able 

 to find any published description or mention of the name in print. Mr. 

 Conrad does not mention it in his enumeration of the species in lhG6, in 

 the Am. Jour. Conch., Vol. II, p. 103; nor is it mentioned by Mr. Gabb or 

 Mr. Meek in catalogues, or by Dr. Stoliczka in the Palaeont. Indica. It is 

 possible I may have overlooked it in some of Mr. Conrad's later publi- 

 cations; therefore I have adopted the name used by him on the label. 



Formation and locality. — In the Lower Marls at Crosswicks, New Jersey. 

 From the collection of the Academy of Natural Sciences at Philadelphia. 



VenieUa trapezoidea. 

 Plate XIX, Fig. 3. 



Venilia trapezoidea Conrad. J. A. N. S., 2d ser., Vo\, IV, p. 282, PI. XLYII, Fig. 7. 



Gabb, Syn. Cret. Form., p. 178. Meek, Check-list Smith. Inst., p. 13. 

 VenieUa trapezoidea (Con.) Stoliczka. Pal. Indica, Yol. Ill, p. 189. 



Shell rather small, trapezoidal in form, but often subtriangular, as seen 

 in internal casts. Valves moderately ventricose, with moderately strong 

 beaks, situated near the anterior third of the length. Hinge short, very 

 slightly arcuate, the margins inflected, forming a slight escutcheon. Ante- 

 rior side of the beaks contracted, throwing the anterior extremity of the 

 shell below the median line, and giving it a narrowly rounded form; basal 

 line gently arcuate, and the posterior margin obliquely truncate, much 

 shortened above and leaving the postero-basal angle somewhat pointed. A 

 strong angular umbonal ridge extends from the beak to the basal angle, 

 giving an abruptly sloping form to the postero-cardinal portion of the shell. 

 Surface marked by concentric lines and by one or more stronger varices of 

 growth. 



