172 BUI.I.BTIN 31 17^ 



cies ; yet upon the whole it seems best placed with Semele, 

 though lateral teeth are scarcely perceptible. The pit for the 

 internal ligament is deep and well-developed ; the exterior liga- 

 mental groove is of moderate length and size. 



Conrad seems to have forgotten this species in his list of 

 1865. 



The muscular scars can just be made out, but the pallial 

 line and sinus seem not to have been impressed in the least. 



We obtained our one valve from the Claiborne "sand", 

 Claiborne, Ala. 



Semele australina, n. ap., PI. 52, Figs. 9, a, b 



Speafic characterization. — Shell ellipso-quadrate as indicated 

 by the figures ; surface practically smooth with a few impressed, 

 distant growth lines ; posterior radiate plication and sulcation as 

 in Tellina raveneli and Semele linosa ; valves shallow in com- 

 parison with ^. profunda, hinge much more delicate ; the liga- 

 ment is separated from the resilium by the strong shell margin; 

 just in front of the resilium is a weak oblique tooth, still in ad- 

 vance is a stronger tooth before which is a pit fsee pi. 52, fig. 

 9 a.). 



The above description applies to the left valve, the only one 

 thus far known in perfect condition. 



A large smooth specimen from the Rio Grande, (probably 

 belonging to this species) is figured herewith (fig. 10). 



The smooth surface, sharp, deep, posterior fold and sinus, 

 and the semi-quadrangular form serve to distinguish this species 

 at once from Conrad's linosa, from the same horizon. 



Type. — Paleont. Mus. C. U. (From Orangeburg District, 



S. C.) 



Horizon. — St. Maurice Eocene. 



Specimens figured. — Figs. 9, a b, Orangeburg District, S. C. 

 Fig. 10, 15 miles below Carrizo Cr., Rio Grande, Tex. 



