72 PALEONTOLOGY OF NEW JERSEY. 



Venus (Abtein'a) staminea. 



Plate XIII, Figs. 3-10. 



Cytherea staminea Conrad; Mioceue Foss., PI. xxi, tig. 1; Am. Jour. Concb., vol. 6, 



p. 76. 

 Dione (Gytherea) staminea Conrad; Proc. Acad. Nat. Sci. Phil., 1862, p, 575. 

 Dione staminea (Conrad) ; Meek Check List, Miocene Foss., p. 10. 

 ? Venm latiUrata (Con.) Heilpriii; Proc. Acad. Nat. Sci. Phil., 1887, p. 403. 



The only description g-iven of the species by Mr. Conrad which I have 

 been able to find is that in vol. (I, p. 7(3, of the Am. Jour. Concli., where he 

 says: "The species is triangular, very ventricose, slightly contracted poste- 

 riorly, and between the ribs are close, minute, rugose, concentric lines [;] 

 umbonal slope terminal, angular; posteiior slope depressed, lunule cordate." 



Two single valves itf small size are all that represent this species 

 among the collections from New Jersey. These are triangular in outline, 

 with deep valves, and the surface is marked with three and four strong, con- 

 centric, recurved, lamellar folds, and the shells are less than half an incli 

 in their greatest diameter. A large entu-e individual from South Caro- 

 lina, however, serves to give the true adult featm-es. This shell is triangu- 

 larly circular in outline and \ery ventricose; the l)eaks are rather small 

 a.nd somewhat appressed, but strongly incurved, directed forward, and 

 placed in advance of the median line; base of the shell very gibbous with 

 a strong constriction just in front of the umbonal margin; anterior end 

 rounded and the posterior umbonal margin strongly arched; lunule large, 

 deeply marked, and l)roadly cordate; posterior slope incurved and depressed 

 below the umbonal margin; posterior end slightly produced. Disk of the 

 valve ventricose, with a strongly marked sulcus just anterior to the umbonal 

 margin. Surface marked by distant, strongly elevated, lamellose, concen- 

 tric ribs and by very fine rugose lines between. Shell substance thick. 

 In the interior the hinge plate is Ijroad with strong teeth separated by deep 

 pits; muscular scars distinct and the pallial sinus small and angular; mar- 

 gins of the valve tinely crenulated. 



The specimen from which this description is taken is more fully g-rown 

 than that hgured by Mr. Conrad in liis Miocene fossils, and shoAvs the pos- 

 terior sulcus, just in front of tlie terminnl uiiil)onal ridge very decidedly. 



