46 PROCEEDINGS OF THE ACADEMY OF [1895. 



PELECYPODA. 



Genus MODIOLA. 

 Modiola houstonia sp. nov. PL 1, fig. 1. 



Specific characterization. — General form of shell as figured; thin, 

 showing concentric lines of growth on the area below the umbonal 

 ridge ; above the same, with broad concentric undulations, becoming 

 more numerous towards the umbones ; anterior, radially striate. 



Localities. — Three miles northeast of Crockett, Houston Co., Tex. ; 

 also five miles northwest of Orangeburg, S. C. 



Geological horizon. — Lower Claiborne Eocene. 



Type. — In Texas State Museum. 



Modiola texana Gabb. PI. 1, fig. 2. 

 Perna texana Gabb, Proc. Ac. Nat. Sci. Pbila., 1861, p. 371. 



The collections of the Survey have yielded few and imperfect 

 specimens of this species. 



Localities. — Caddo Peak, Texas, Gabb. Two miles southwest of 

 Campbellton, Atascosa Co. ; two miles east of Arnold's ranch, Frio 

 Co., Tex. Near Red Laud, La. 



Geological horizon. — Lower Claiborne Eocene. 



Specimen figured: From near Red Land, La., property of U. S. 

 Nat. Museum. 



Type. — In the Academy of Natural Sciences of Philadelphia. 



Genus LEDA. 

 Leda bastropensis nov. sp. PI. 1, fig. 3. 



Specific chararlerizntion. — General form as figured; medial por- 

 tions of the valves with regular, strong, concentric stria?; stria? ob- 

 solete on the anterior end and on the post-umbonal slope, the latter 

 with a shallow furrow extending from the umbo to near the ex- 

 tremity of the valve; within the valve, a raised line or ridge, emanat- 

 ing from the umbonal region and extending along beneath the 

 hinge finally terminates in the middle of the posterior end and is 

 there slightly enlarged. 



This species differs from L. plicata Lea in its lack of striation 

 over portions of the exterior, and the more central positions of the 

 umbones. From L. mater Mr., bastropensis is distinguished by its 

 want of anterior radiating sulci, its lack of post-umbonal striation, 

 and by its form. This is readily distinguished from L. albirupina 



