American Tertiary Shells 



Genus CORBULA Bruguiere 

 Anapteris, new subgenus 



Description. — Lesser or left, onl}- valve known ; large, flat, 

 surface of shell stronglj- corrugated, this corrugation extends 

 to the anterior margin where the extreme, anterior portion of the 

 valve appears as though it had been broken ; on the interior of 

 the shell this area corresponds to a wing or flare which is bounded 

 below b)' a strong ridge ; this ridge suggests the original margin 

 of the valve. The wing bears ver}- fine, radiating striae. 



Anapteris regalis, n. sp., ' ■ PI. i Fig. i. 3 



Description. — Size and shape of shell as indicated by the fig- 

 ures. Left valve nearly flat, thick, dorsal margin bent out- 

 ward, giving intimation of a gape ; a pronounced carina extends 

 from the beak to the posterior margin. Surface ornamented with 

 prominent, concentric lines which extend from the umbonal 

 ridge to the anterior end where they terminate in a peculiar 

 manner as though the anterior end had been broken ; on the 

 posterior portion of the shell anterior to the umbonal ridge where 

 the lines merge into the ridge a separation of the lines occurs 

 giving place to very short, equally prominent, surface markings. 

 Ju.st anterior and parallel to the umbonal carina is a fine channel; 

 the prominent lines posterior to the umbonal ridge extend almost 

 verticall}- to the dorsal margin. On some specimens two slight 

 channels are noted which are situated between the dorsal margin 

 and the posterior ridge and extend from the beak to the poster- 

 ior margin ; on the anterior internal surface of the left valve a 

 raised margin-like ridge extends from the beak concavely, 

 and then rounds into the ventral margin ; the portion of the shell 

 dorsal to the ridge has the appearance of a flare or wing. The 

 projecting, cartilage process in the left valve in this form differs 

 from that in the genus Corbula, in having onl)- a very narrow, 

 .short, posterior groove ; the anterior groove is slightly marked, 

 in .some ca.ses practically ob.solete. 



Types and specimens figured. — Paleontological Mu.seum, Cor- 

 nell Univ. 



