PLEIOCENE FOSSILS. 35 



ARCA INCILE.— Say. 

 Plate XIV., Figs. 6 and 7. 



Area incile, Say, Jour. Ac. Nat. Sci., Vol. IV., p. 139, pi. 10, fig. 8. 

 Area incile, Con., Foss. Shells, Ter. For. p. 16, tab. 2, fig. 1. 

 Area incile, Con., Foss. Ter. For., p. 56, pi. 29, fig. 5. 



A. testa oblique ovata, radiatim costata ; costis inequalibus ; latere buccali brevissimo ; 

 latere anali compresso, angulato, truncato, vix emarginato, carinato ; area ligamenti lata; 

 umbonibus incurvis, approximatis. 



Description. Shell obliquely ovate, radiately ribbed; ribs unequal, larger on the anal 

 side ; buccal side very short ; anal side compressed, angular, truncate, nearly emarginate, 

 carinate ; umbones incurved, approximating. 



The ligament area is crossed at the buccal extremity by close transverse lines, the rest of 

 the area is impressed by the lines of growth parallel with the hinge ; teeth regular and 

 oblique towards the anal margin. This fossil is readily distinguished by the much con- 

 tracted buccal side, which is most striking when the interior of the shell is towards the 

 observer, and by the abruptly compressed and carinated anal side. 



Plate XIV., Fig. 6. Exterior of upper, and interior of lower valve. 

 " 7. End view, to show the hinge. 



Locality. Darlington District. 



Museum, College of Charleston, 



10 



