634 SYSTEMATIC PALEONTOLOGY 



Anatina elliptica Conrad, 1868, Cook's Geol. of New Jersey, p. 727. 

 Periplomya elliptica Gabb, 1876, Proc. Acad. Nat. Sci., Phila., p. 305. 

 Periplomya elliptica Whitfield, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 177, 



pi. xxiii, figs. 14, 15. 



Periplomya elliptica Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 13. 

 Periplomya elliptica Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, 

 p. 522, pi. Ivii, figs. 8-11. 



Description. " Shell subelliptical, equivalve, nearly equilateral ; beak 

 central, pointing posteriorly, very small, umbones small. Cardinal mar- 

 gin slightly convex. Buccal margin broad, nearly straight and sloping 

 inwards towards the basal edge, which is very broadly rounded, being 

 nearly straight just opposite the beaks. Anal extremity hardly more than 

 half as broad as the buccal, and with the hinge line between it and the 

 beaks, regularly concave. There is a broadly rounded ridge extending 

 from the umbones towards the anterior basal margin, gradually becoming 

 obsolete as it approaches the edge. Shell thin, and marked on the surface 

 by small, irregular concentric ridges. Length 0.9 inch (from beaks to basal 

 margin), width 1.3 inch." Gabb, 1862. 



Type Locality. Mullica Hill, New Jersey. 



" Shell small, inequivalve, and very inequilateral, subovate in outline, 

 largest across the anterior side of the beaks, and strongly constricted just 

 behind them, the posterior end being narrowed on the hinge line and exca- 

 vated at this point. Valves somewhat ventricose, the right one less con- 

 vex than the left, and very decidedly depressed in the central region and 

 toward the basal line, showing a decided twist or arcuation of the valves as 

 seen in a basal view. Anterior end broadly rounded, and the posterior 

 pointedly rounded. Beaks small, appressed, incurved, and apparently 

 directed backward, as is usual in this group of shells, from the expansion 

 of inflation of the anterior side of the hinge line. Cardinal margin, as 

 seen on the cast, inflected both in front of and behind the beaks, forming 

 an apparent lunule and escutcheon on the cast, probably produced mainly 

 from a thickening of the hinge plate within. Muscular imprints and 

 pallial line and hinge not observed." Whitfield, 1885. 



A single imperfect cast has been referred to this species. It shows, 

 however, the compressed valves, the acute umbones and the constriction 

 behind the umbones which characterize the species. 



