12 AMERICAN JOURNAL 



to be nearly related to the Carditamerce, but the hinge character 

 is not very clearly represented. It is sufficient, however, to show 

 a decidedly new generic form, as it wants the long, slender pos- 

 terior cardinal tooth of Carditamera, Conrad, (Lazaria, Grray,) 

 and the anterior cardinal tooth of the right valve is represented 

 as thick and tuberculiform, whilst in the latter genus there is no 

 distinct tooth but only a small fosset. The other shells referred 

 to Cardita are probably all congeneric with C. Austriaca. See 

 Stoppani's Palneont. Lomb. Monog. des Foss. De L'Azzarola, p. 

 53 — 7. 



PLEUROMERIS, Conrad. 



Description. — Equivalve, triangular, radiately ribbed ; hinge 

 in the right valve with one -broad, nearly direct concave or 

 broadly furrowed recurved tooth, the upper extremity acute and 

 opposite or above the apex of the shell ; hinge in the left valve 

 with three teeth, the anterior one small and fitting into a cavity 

 in the opposite valve. 



Pleuromeris decemcostata, Conrad. 



Description. — Triangular ; ribs twelve, rounded ornamented 

 by numerous angular or transverse tubercles over all the ribs. 



Cardita tridejitata, Conrad, (not Say.) — Tertiary Foss. of the 

 U. S., p. 76, pi. 43, fig. 11. 



Observations. — This shell is nearly related to Say's tridentata., 

 but has only twelve ribs, whilst Say's -species has eighteen, and 

 the elevated concentric lines are said to be obsolete on the anterior 

 side, but in our fossil the tubercles or lines are most prominent 

 on the anterior side. 



I have not seen a specimen of Say's species, and therefore 

 cannot say whether it should be referred to this genus. 



The shell described and figured by Reeve in Conchologia 

 Iconica as Cardita tridentata, Say, is a far larger and difi'erent 

 species from the tridentata. 



ASTARTID^. 

 ASTARTE, Sowerby. 

 Astarte corbicula, Conrad. 



Desc7'iption. — Subtriangular ; posterior margin truncated, di- 

 rect, ribs fifteen, prominent, concentric, imbricated, the inter- 

 stices transversely striated ; beaks distant from the anterior end ; 

 lunulo cordate, impressed ; inner margin crenulated. Length 

 quarter of an inch. 



A. crenulirata, Lea, (not Conrad.) — Proceed. Acad. Nat. 

 Sciences, 1861, p. 150. 



Locality. — Haddonfield, N. J. 



