60 PALEONTOLOGY OP NEW JERSEY. 



Family CRASSATELLID^. 

 Genus CRASSATELLA Lamarck. 



Cbassatella melina. 



Plate viii ? figs. 11-13. 



Cra8satella melina Conrad; Foss. Shells of the Tert. Form. N. A., p. 23, PL ix, fig. 2; 

 Medial Tert. Form., p. 22, PI. xn, fig. 2; Meek, Smith. Check List, p. 7. 



Mr. Conrad describes this shell originally from Cumberland County, 

 N. J., as follows: "Shell subovate, convex-depressed; umbones with a few 

 regular rather wide sulci; umbonal slope nearly rectilinear, angular; dorsal 

 margin very slightly concave; extremity obliquely truncated; anterior mar- 

 gin regularly rounded." In his observations he says it differs from C. undu- 

 lata in being proportionally much shorter, and more widely truncated at 

 the extremity, while the dorsal margin is less concave; and from the (7. 

 Marylandica in "being thinner and more compressed." 



The shells, as I find them, are broadly subovate, much the widest ante- 

 riorly, with the apex of the valves at about two-fifths of the entire length 

 from the anterior end. The posterior cardinal margin slopes rapidly, and 

 with but little concavity, from the beak to the posterior end which is usually 

 about half as high as the shell from the beak to the basal margin opposite. 

 The body of the shell is rather convex, especially in old thickened speci- 

 mens. The umbonal ridge is somewhat angular and the posterior umbonal 

 slope rather abrupt. Mr. Conrad states that it is thinner than C. Marylandica. 

 If by this is understood the thickness or weight of the shell, some of the 

 specimens before me would not bear out the observation, as they are greatly 

 thickened, and in comparison to the size of the shell would appear to be 

 heavier than any individuals of that species I have noticed. Or if he 

 referred to the general convexity of the valves, many of them are very 

 rotund; although the majority are perhaps* rather depressed convex. The 

 hinge of the shell is very strong, and usually quite wide, but the teeth are 

 comparatively thin and slender, while the ligamental pit is broad and well 

 defined. The muscular imprints are large and deeply marked. -A peculiar 

 feature noticeable among the sheik is a tendency of the surface to exfoliate 



