127 St. Maurice and Claiborne PeivECypoda 127 



. Specimens showing interior characteristics are very rare, 

 and we have found none showing in a satisfactory manner the 

 characteristics of the muscular scars. The more robust develop- 

 ment of the teeth in this species, as compared with the specimens 

 Conrad studied suggest the modifying of his generic description 

 so as to include the strong, sickle-shaped anterior in the right 

 valve and the decidedly bifid or twinned anterior cardinal in the 

 left valve. The long, posterior cardinals are remarkable in their 

 greatly developed, practically free, posterior extension and inter- 

 locking character. Conrad's Miocene "tj^pe" form unfortunate- 

 1}^ represents a decadent and senile strain of this virile genus. 

 This fact has doubtless led to such statements as : "It is evident, 

 therefore, that Sphcsrella can be regarded at most as a section of 

 Diplodojita, closely allied to the typical form of that genus." 

 Again, regarding the species in question ; "This remarkable 

 globular species is not a Sph(B)'ella, but simply a turgid Diplo- 

 donta." (Trans. Wag., Ill, p. 11 82). 



This species is well distributed in Texas, but perhaps no 

 other locality can well compare for abundance and size and var- 

 iety of specimens with St. Maurice, La. 



Type. — Singley's Collection, Tex. 



Horizon . — St . Maurice Eocene . 



Specimens Jigured. — Deposited in Paleont. Coll. Cornell 

 Univ., from St. Maurice, La. 



Localities. — Texas : Cedar Creek, Wheelock League, Robert- 

 son Co., cutting on Tyler and S. E. R. R., 400 yds. S. of mile 

 post No. 23, Cherokee Co. ; Dr. CoUard's farm. Sparks Head- 

 right, Brazos Co.; Elm Creek, Lee Co.; Smithville. La.: 

 St. Maurice, Natchitoches, Vivian, Marble Q'y, ? Cedar Bluff, 

 Sabine R. Miss. : McLeod's Mill, Suwanlovey Cr., Clark Co. 



Diplodonta ungulina, K. 4°. Figs. 10-14. 



Astarte unglina Con., Am. Jr. Sci., vol. 23, 1833, p. 342. 

 Egeria rotunda I^ea, Cont. to Geol., 1833, p. 50, pi. i, fig. 17. 

 Diplodonta astartiforuiis Con., Jr. Phila. Ac. Nat. Sci., i860, vol. 4, 



296. 

 Diplodonta deltoidea Con. Jr. Phila &c., vol. 4, p. 296. 



