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. An. des Mus. v. 9, pi. 

 31, fig. 10. An. 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 

 London Clary, 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 f 6, fig. \. 



Lentiform, with numerous concentric stria?, 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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