PHC-LADIDJ3. 57 



Genus, SAXICAVA.— Fleuriau de Bellevue. 

 Genus, BYSSOMYA.— Cuv. 



SAXICAVA FRAGILI S. — fNeiv Species.) 

 Plate VIII. Fig. 18. 



Description. — Shell oblong, fragile, concentrically striated, somewhat laminated; 

 anterior and posterior margins obtusely rounded; dorsal margin straight, or slightly curved 

 towards posterior end; pallial margin compressed in the middle; umbones anterior, 

 depressed; pallial impression distinct, simple, at a distance from margins; cardinal tooth 

 in both valves, prominent, nodulous. 



We have the right and left valve of this shell from the Post-Pleiocene ; it is not known 

 on the coast. 



Plate VIII. Fig. 18, Right valve, natural size. 



Locality. Simmons'. Cabinet F. S. H. 



Genus, PHOLAS.-Linn. 



PHOLAS TRUNCATA. 

 Plate IX. Pig. 4. 



Pholas truncata, Say, Jour. Acad. Nat. Sci., Vol. 2, p. 223. 



Pholas truncata, De Kay, Zool. New-York, Art. Mollusca, p. 248, pi. 34, fig. 223. 



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



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



Pholas truncata, Say's Conch. U. S., (Binney,) p. 107. 



Description. Shell transversely oblong, sub-pentangular; anterior margin rostrated, 

 obtusely cuneiform in the middle; posterior margin broadly truncated at tip; valves 

 transversely wrinkled and longitudinally striated, muricated, particularly on the anterior 

 side, with small erect scales, which are not arched beneath; posterior margin from a line 

 extending from the beak to the inferior angle of the truncature, destitute of the striae and 

 mutic; hinge callous, formed of the duplicature of the hinge-margin, and destitute of 

 cells; a small tooth upon the inner margin, projecting backwards; dentiform process 

 curved, prominent, slender, flat. — Say. 



Plate IX. Fig. 4, Shell, natural size. 



Locality. Simmons'. Museum, College of Charleston; Cabinet F. S. H. 



15 



