80 PALEONTOLOGY OF NEW JERSEY. 
the other. Hinge in the left valve with a small triangular tooth beneath 
the beak, which is nearly direct, and a very distinct ligamental pit which 
is much elongated and very oblique. 
Only two specimens of this shell, both left valves and both imperfect, 
have been observed. The length is less‘than half an inch. I have been 
unable to identify it with any described species, recent or fossil. 
Locality: In the gray marls of the Miocene at Shiloh, N. J. From the 
cabinet of the National Museum. 
ABRA AEQUALIS. 
Plate xrv, figs. 11-15. 
Amphidesma aequalis Say: Jour. Acad. Nat. Sci. Phila., 1st ser., vol. 2, p. 307; Am. 
Conch., Pl. xxvi1; Conrad, Miocene Foss., p. 76, Pl. x11, fig. 9; Tuomey and 
Holmes, Plioe. Foss. 8. Car., p. 93, Pl. xxi, fig. 3. 
Abra aequalis (Say) Conrad: Proc. Acad. Nat. Sei. Phila., 1862, p. 574; Meek, Check 
List Miocene Foss., p. 11. 
“Shell orbicular, slightly oblique, polished, white, with very minute 
and numerous concentric wrinkles near the margin, which are obsolete on 
the disk and umbo; lateral teeth none, primary teeth two in the left valve 
and one in the other; interior ligament cavity subfusiform, as long as the 
exterior ligament.” (Say’s description of recent shell.) 
A few very perfect specimens of this species have been obtained, the 
characters of which are so perfectly similar to those of the living shell as 
to leave no question of their identity. They vary somewhat among them- 
selves in regard to the relative position of the beaks, but the recent forms 
present the same differences. The shells are thin and fragile, and only 
moderately convex, of a broad-ovate form in outline, the beaks at about 
one-third of the length from the anterior end, small and inconspicuous, with 
a low inconspicuous ridge passing from them to the antero-basal margin, 
and the surface marked by very fine, concentric, somewhat wrinkled lines 
or ridges. In the interior the cardinal tooth is small, and the laterals rather 
large, ligamental pit narrow, very oblique and of moderate length. It is 
a very neat and pretty shell, and moderately abundant. 
Formation and locality: The specimens are from Jericho, N. J., and 
belong to the National Museum collection. 
