56 PLBIOCENE FOSSILS. 



Mr. Conrad supposes this species identical with his L. Floridana, a recent species from 

 the Florida coast, which we have not seen. 



Occurs abundantly in the Meiocene of Virginia, but is rather rare in South-Carolina. 



Plate XVIII. Fig. 2, Interior of right and exterior of left valve. 



Locality . Waccamaw. 



Museum, College of Charleston. 



LUCINA PENNSYLVANIA.— Linn. 

 Plate XVIII. Fig. 3. 



Venus Pennsylvanica, Linn, Sys. Nat., (Ed. Tur.) Vol. 4, p. 232. 

 Lucina Pennsylvanica, Lam., (Ed. 3rd) p. 574. 

 Lucina Pennsylvanica, Sow., Sow. Gen., No. 27, fig. 4. 

 Lucina Pennsylvanica, Reeve, Reeve's Con. Icon., pi. 4, fig. 29. 



L. testa sub-cjlobosa, crassa, solida, concetitrice multilivata; latere anali sulcato-excavata; 

 lunula ampla ollongo-cordata impressa. 



Description. Shell sub-globose, thick, solid, concentrically ribbed; anal side with a 

 conspicuous channel; lunule impressed, oblong, cordate. 



This is a well-characterised species. The deep channel on the anal side, which pro- 

 duces a notch in the pallial margin, the flat concentric ribs on the disks, the well-defined 

 ovate lunule, and the angle on the buccal side, are characters that distinguish this species 

 from all its congeners. 



With age, the shell becomes very thick, and the muscular impressions deep. Towards 

 the pallial margin the lines of growth become somewhat lamellcse. 



Reeve gives a figure of a specimen from Jamaica, and seems to doubt its existence on 

 our coast, but occasionally a valve is picked up on the coast of South-Carolina; and on 

 the southern coast of Florida it is one of the most common shells. 



Plate XVIII. Fig. 3, Interior of right and exterior of left valve. 



Locality, Darlington District. 



Museum, College of Charleston. 



