58 POST-PLEIOCENE FOSSILS. 



PHOLAS COSTATA. 



Plate IX. Figs. 1 and la. 



Pliolas costata, Linn., Syst. Nat,, 1111. 



Pholas costata, Lam., An. sans Vert., VI., 45. 



Pholas costata, Wood, Gen. Conch., pi. 15, figs. 1 and 2. 



Pliolas costata, Gould, Invert. Mass., p. 26. 



Pliolas costata, Ravenel, Cat. Coll. Shells, p. 2. 



Pholas costata, L. R. Gibbes, Tuomey's Geol. So. Ca., appendix, p. xxii. 



Pholas costata, Tuomey 4- Holmes, Pleiocene Foss. So. Ca., p. 102, pi. 24, fig. 4. 



Description. Shell large, thin, oblong-ovate; buccal margin rounded, anal margin 

 more pointed; dorsal margin reflected over the umbones; ribs radiating, with coarse lines 

 of growth, producing tooth-like elevations at regular intervals on each rib. 



This is the most common of the three species of Pholadid^e on the Southern coast, and 

 is abundant in the harbors of this State. It often attains the width of six inches. 



Plate IX. Fig. 1, Fossil, natural size; bach view, showing accessory valve. 

 " la, Side view, left valve. 



Locality. Simmons'. Museum, College of Charleston. 



Genus, DACTYLINA.— Gray. 



DACTYLINA OBLONGATA. 

 Plate IX. Fig. 2. 



Pholas oblongata, Say, Jour. Acad. Nat. Sci., Vol. 2, p. 320. 



Pholas oblongata, Ravenel, Cat. Coll. Shells, p. 2. 



Pholas oblongata, L. R. Gibbes, Tuomey's Geol. So. Ca., appendix, p. 22. 



Pholas oblongata, Tuomey 4- Holmes, Pleiocene Foss. So. Ca., p. 103, pi. 24, fig. 1. 



Description. Shell oblong-ovate, inflated, transversely and longitudinally striated; 

 striae muricated, and elevated on the buccal side into ribs; buccal margin acutely rounded; 

 anal margin compressed ; dorsal margin anteriorly reflexed, forming a cavity ; hinge 

 callous, minutely striated transversely and longitudinally, and with about twelve 

 cells.— T. Sf H. 



