40 PLEIOCENE FOSSILS. 



ARCA LIENOSA.— Say. 



Plate XV., Figs. 2 and 3. 



Area Lienosa, Say., Say's American Conchology, plate 36. 



A. testa oblonga, obliqua, inflata, costata, transversim rugosa ; latere buccali producto, 

 angulato ; latere anali elongate-, oblique truncate ; costis inaiqualibus sulcatis ; area ligamenti 

 lata sulcata, umbonibus distantibus. 



Description. Shell oblong, oblique, inflated, ribbed, transversely rugose, buccal side 

 produced, angular ; anal side elongated, obliquely truncate ; ribs unequal, channelled ; liga- 

 ment area wide sulcate ; umbones distant. 



The ligament area is bounded on the outer side by a short carina, crossed by close lines, 

 which are well defined towards each extremity. The sulci of the area are not regularly 

 diverging, but somewhat parallel to the hinge. The ribs in young shells are impressed by 

 a line to which others are added, after the shells have attained a certain size ; the ribs are 

 larger on each extremity of the shells, and on the buccal side are about equal to the inter- 

 stices. The concentric lines of growth are raised and prominent towards the margin, and 

 in old specimens become even rugose. This species occurs recent on the coast of Florida. 



Plate XV., Fig. 2. Exterior of left valve, and hinge and teeth of right valve. 

 " 3. End view, showing outline of hinge and umbones. 



Locality. Tilley's Landing, Waccamaw. 



Museum, College of Charleston. 



