MIOCENE MOLLUSCA AND CRUSTACEA. 43 
erated by the subsequent deposit from the interior by additional growth 
of the shell. 
Localities: The only specimens seen from New Jersey are from Shiloh 
and vicinity. The species is abundant at many localities in Maryland, 
Virginia, and in North and South Carolina. Collection at Rutgers College 
and National Museum. 
ARCA (SCAPHARCA) CALLIPLEURA. 
Plate v1, figs. 8 and 9. 
Arca callipleura Conrad: Miocene Foss., p. 54, Pl. xxrx, fig. 2. 
Scapharca callipleura Conrad: Proce. Acad. Nat. Sei., Phil., 1862, p. 579. 
Scapharea callepleura (Conrad) Meek: Check List Mioc. Foss., p. 6. 
“Shell subtrigonal, profoundly ventricose, thick, posterior area flattened 
and very wide; posterior end oblique, emarginate; ribs little elevated, flat- 
tened, with an impressed line in the middle of each, and another fine line 
on each side of the central one; the ribs are beautifully granulated; beaks 
very prominent and distant; inner margin with narrow very prominent 
teeth.” 
Mr. Conrad states that of this species he has seen but a single valve; 
it therefore might be considered arare species. Still among the specimens 
obtained in the well boring at Mr. L. Woolman’s, at Atlantic City, quite 
a large fragment occurs which can not be referred to any other than this 
shell, and at the same time leaves scarcely any doubt that it pertains 
to this species. The fine line on each side of the medial impressed line of 
the ribs can not be detected, but the shell has been subject to some action 
in the bed, so as to leave the impress of the grains of sand on the surface, 
and thus obscure any finer markings which may have existed. I have 
figured the fragment as perfectly as it will permit, and I think it leaves no 
doubt as to its relations to the figure given by Mr. Conrad, and also 
copied on the plate here. 
The specimen belongs to the Academy of Natural Sciences at Phila- 
delphia. 
. 
