52 POST-PLEIOCENE FOSSILS. 



SEMELE TRANSVERSA 

 Plate VIII. Fig. 10. 



Amphidesma transversa, Say, Am Conch., pi. 28 



Amphidesma transversa, De Kay, Zool. Nevv'-York, Art. Mollusca, p. 237. 



Amphidesma transversa, Say's Conch. U. S., (Binney,) p. 181. 



Description. Shell thin, sub-oval, nearly equilateral, compressed ; buccal and anal 

 margins sub-equally rounded ; beaks slightly prominent, basal margin regularly rounded. 



This shell is now living on the Northern coast of the United States. Mr. Say obtained 

 a specimen from the coast of Georgia, which he says was somewhat worn ; was it a Post- 

 Pleiocene fossil ? 



Plate VIII. Fig. 10, Fossil, natural size. 



Locality. Abbapoola Creek. Museum, College of Charleston; Cabinet F. S. H. 



SEMELE RADIATA. 

 Pl.we Vin. Fig. 11. 



Amphidesma radiata, Say, Jour. Acad. Nat. Sci., Vol. 5, p. 220. 

 Amphidesma radiata. Say, Conch. U. S., (Binney,) p. 127. 



Description. Shell transversely oval, orbicular, a little compressed; apex nearly 

 central, a little prominent; posterior slope somewhat concave near the beak; anterior slope 

 rectilinear to the middle; disk somewhat regularly wrinkled transversely, and with minute 

 longitudinal striae; anterior sub-margin, with a very slight obtuse undulation; cardinal 

 teeth two in each valve, elevated, slender, unequal ; lateral teeth very distinct; interior 

 ligamental cavity profound, fusiform. — Say. 



Our specimen is a single valve only of a young shell. It is not known to be living upon 

 the Carolina coast, but Mr. Say had specimens from the shores of East Florida, and one 

 shell from the coast of Georgia. 



Plate VIII. Fig. 11, Shell, natural size. 



Cabinet F. S. H. 



