94 POST-PLEIOCENE FOSSILS. 



the edge thin and sharp ; whorls three in number, rapidly enlarging ; surface smooth and 

 glossy, indistinctly striated with lines of growth ; lip not thickened ; diameter an eighth 

 of an inch." — Stimpson. 



The shell represented in our figure, from the Post-Pleiocene, diflfers very little from the 

 description of the recent shell, as given above ; the fossil is thicker in substance than 

 those which we have obtained from the coast, and those which Messrs. Stimpson and 

 Kurtz found parasitic on Acoetes hipma, a gigantia annelide of the Aphrodite family. It is 

 very common in the fossil state. 



Plate XIV. Fig. 9, Natural size. 

 " 9a, Magnified. 

 " 95, Magnified outline. 



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



FISSURELLA.— Brug. 



FISSURELLA ALTER N AT A. — S a y. 

 Plate XIV. Fig. 10. 



Fissurella alternata, Say, Jour. Acad. Nat. Sci., Vol. 2, p. 224. 

 Fissurella alternata, Ravenel, Cat. Coll. Shells, p. 9. 



Fissurella alternata, L. R. Gibbes, Tuomey's Geol. So. Ca., appendix, p. xx. 

 Fissurella alternata, Saij, Conch. U. S., ed. Binney, p. 73. 



Description. " Shell oblong-ovate, moderately thick, cinerous or dusky, with equal 

 concentric lines, crossed by alternately larger and smaller radii, all which are equable or 

 not dilated in any part : vertex placed nearer the smaller end ; perforation oblique, oblong, 

 and a little contracted in the middle ; within white ; margin simply crenate ; apex with an 

 indented transverse line at the larger end of the perforation." — Say. 



Fissurella alternata is common on the coast of Carolina and Georgia. 



Plate XIV. Fig. 10, Natural size. 



Locality. Simmons' ; Stono River. 



Museum, College of Charleston; Cabinet F. S. H. 



