TELLINID^E. 51 



fusiform, parallel with posterior"slope. This shell resembles Amphidesma punctata, of 

 Say, but it is readily distinguished by its smooth, not punctured surface, and angular 

 posterior side. It is abundant in the Post-Pleiocene, and though dead shells are often 

 found on our beaches, we have not yet discovered a living specimen on the coast of South- 

 Carolina. 



Plate VIII. Fig. 8, Valves, natural size. 



Locality. Simmons'; Abbapoola Creek; Artesian Well, Charleston. 



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



Genus, SEMELE. — Schumacker. 



SEMELE OEBICULATA. 

 Plate VIII. Pig. 9. 



Amphidesma orbiculata, Say, Jour. Acad. Nat. Sci., Vol. 2, p. 307. 



Amphidesma orbiculata, Ravenel, Cat. Coll. Shells, p. 3. 



Amphidesma orbiculata, De Kay, Zool. New- York, Art. Mollusca, p. 237. 



Amphidesma orbiculata, L. R. Gibbes, Tuomey's Geol. So. Ca., appendix, p. xxii. 



Amphidesma orbiculata, Tuorney $ Holmes, Pleiocene Foss. So. Ca., p. 94, pi. 23, fig. 4. 



Semele orbiculata, Adams, Gen. Recent Shells, Vol. 2, p. 411. 



Amphidesma orbiculata, Say's Conch. U. S., (Binney,) p. 100. 



Description. Shell orbicular, sub-compressed; surface finely marked with concentric 

 lines of growth, which are interrupted irregularly with raised sub-laminated concentric 

 lines; buccal margin obtusely undulated; interior ligamental-cavity profound, fusiform, 

 parallel with marginal slope, and extending from tip of beak. 



In young shells, longitudinal, radiating, and obsolete lines are distinctly seen intersecting 

 the lines of growth, but in older specimens a few lines only are visible upon the buccal 

 folds or undulations. — T. c\ H. 



This species is abundantly fossil in the Post-Pleiocene, and is recent on the coast of 

 the State. 



Plate VIII. Fig. 9, Exterior of shell. 



Locality. Simmons'. Museum, College of Charleston. 



