58 PALEONTOLOGY OF NEW JEESEY. 



agree very well indeed with his species C. protraqta. There is one feature of 

 this species in which it appears to differ materially from C. protracta, viz, 

 the -"dilation" of the extremity of the three large ribs of the posterior end. 

 Among the specimens which I have examined this is generally a marked 

 feature. The three ribs which occur on the umbonal ridge project beyond 

 the others so as to prolong the margin of the valve; and the three, or gen- 

 erally four, small ribs above them, on the posterior slope, contract the pos- 

 terior truncated margin by their smaller size. The disk of the valves is 

 usually broadly sinuate or depressed from behind the beak to the base of the 

 shell, although the ribs gradually increase in size from the most anterior to 

 the one which runs along the umbonal ridge. The surface of the ribs are 

 very strongly crenulated by the coarse concentric stride of growth, and near 

 the posterior cardinal border are often prolonged into short, recurved, spi- 

 nose processes. In the older specimens the inner margin is strongly den- 

 ticulated and the muscular imprints strongly marked. The hinge plate, 

 however, is rather slight and narrow. 



Localities: In New Jersey the species has been found at Shiloh, Jericho, 

 and Bridgeton. At Jericho it does not appear to be uncommon, although 

 seldom of large size. From the collections of the National Museum prin- 

 cipally. A few also from those at Rutgers College. 



Carditamera aculeata. 

 Plate ix, figs. 7 and 8. 



Carditamera aculeata Conrad: Proc. Acad. Nat. Sci. Phil., 1862, p. 585; Am. Jour. 

 Conch., vol. 2, p. 73, PI. IV, fig 5; Meek, Check List Miocene Foss., p. 7; Heil- 

 prin,Tert. Geol. U. S., p. 8; Miocene Moll. New Jersey, Proc. Acad. Nat. Sci. 

 Phil., 1887, pp. 397, 398, and 403. 



Comp. G. arata Con. in the young stages of growth. 



In Conrad's original description of this species he says: " Trapezoidal; 

 umbonal slope inflated; base emarginate; ribs on anterior side crenulated, 

 on the anterior side subspinose." His Second description is as follows: 

 "Trapezoidal inequilateral; umbonal slope ventricose; base emarginate in 

 the middle ; disk contracted in the middle ; ribs very large over the umbonal 

 slope; anterior ribs crenulated; the larger ribs and the dorsal submargin 

 with prominent scales." 



