66 PALEONTOLOGY OF NEW JERSEY. 



Family CARDIID^. 

 Genus CARDIUM Linn. 



Cardium (Cerastoderma) cratiouloides. 



PI. x, figs. 16-19. 



Cardium cratieuloides, Conrad: Mioc. Foss., p. 66, PL xxxvn, fig. 3. 



G. ( Cerastoderma) craticuloides, Conrad : Proc Acad. Nat. Sci. Phil., 1862, p. 576 ; Meek, 



Check List Miocene Foss., p. 8. 

 f C. laqueatum, Heilpin: Proc. Acad. Nat. Sci. Phil., pp. 398, 400, 403. 



" Suborbicular, ventricose; ribs about twenty-nine, very much com- 

 pressed, profoundly elevated, the summits reflected on both sides, conse- 

 quently the ribs are as wide on the back as at base ; summit of the umbo 

 very prominent. 



" Remarkable for the compressed form and great elevation of the ribs 

 which are most remote on the anterior side ; ribs not very regular, but some- 

 what sinuous." (Conrad.) 



The few fragments of Cardium which have been collected from the New 

 Jersey localities are not very satisfactory for study. They are all small, 

 and only fragments of the larger size shells showing the development of the 

 character of the ribs are found. The small specimens which show the apical 

 portion appear to be mostly only the inner shells of the specimens, the outer 

 layers being apparently removed by some process, so that the ribs do not 

 present the true features of the species. After a deal of study I have come to 

 the conclusion that they do not represent C. laqiieatum, as has generally been 

 supposed; but that they are more properly referable to C. craticuloides Con- 

 rad. The number of the ribs, their direction, and their form, as seen on the 

 larger fragments, and the want of the posterior flattening of the posterior 

 slope, as seen in C. laqueatuwi, and lack of obliquity, show this to be the 

 case. I have figured the best fragments which I have examined, and feel 

 certain from the characters there presented that others will agree in this 

 decision. 



Locality and formation : All the fragments seen are from the gray marly 

 layers of the Miocene near Shiloh, or from the more stony layers near 

 Bridgeton, N. J., and are from the collections at Rutgers College or the 

 National Museum. 



