20 
CYPRICARDIA ARATA. Tab. 5 , fig. 1. 
Oblong, with about 15 profoundly elevated scaly ribs; dorsal 
and basal margins parallel; anterior side very short; posterior 
margin oblique, angular above; inner margin crenate. 
Localities. Newbern, N. C. Mr. Nuttall; James River, near 
Smithfield, and York Town, Va.; near Easton, Md.; Cumber- 
land county, N. J. 
CARDITA PLANICOSTA. Tab. 5, fig. 2. 
Cordate; ribs about 22, broad and flattened, separated by a 
narrow groove which becomes obsolete at the base; ribs near 
the posterior end narrow, indistinct, and crossed by numerous 
strong wrinkles; lunule small, cordate, profoundly impressed; 
inner margin crenate. 
Syn. Venericardia. planicosta, Lam . Jin. des Mus. v. 9, pi. 
31, fig. 10. Jin. sans vert . v. 5, p. 609. Sowerby. 
Min. Conch . v. 1, t. 50. 
Localities. Piscataway, Md. Claiborne, Alab. Middle Ter. 
This characteristic fossil is found in the equivalents of the 
Imndon Clay , in England, France, Italy, Piedmont, and Flor- 
ence. Lam. The figure is from an individual found in Mary- 
land; those from Alabama are smaller and more perfect. 
ARTEMIS ACETABULUM. Tab. 6, fig. 1. 
< 00 . 
Lentiform, with numerous concentric strise, which are rather 
sharp and elevated on the anterior and posterior sides; cardinal 
fosset large, oblong, profound; with age, almost obliterating the 
posterior tooth; right valve with three teeth, the posterior one 
long and sulcated longitudinally; two anterior teeth approxi- 
mate; left valve with four teeth, three of them distant; the an- 
terior tooth somewhat pyramidal and entering a groove formed 
by two slight elevations in the opposite valve. 
Localities. St. Mary’s River, and Easton, Md.; James River, 
near Smithfield, and Suffolk, Va. Upper Tertiary. 
This shell has been confounded with Artemis concentrica , 
(Cytherea concentrica) of our coast. 
The species of this genus are still referred to Cytherea by 
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