1895.] NATURAL SCIENCES OF PHILADELPHIA. 47 



Har. since it lacks the smooth Yoldia-like aspect about the umbones 

 so characteristic of that species. 



Localities. — Rio Grande at Starr-Zapata Co. line; Brazos River, 

 one mile below Milam-Burleson Co. line, Tex. 

 Geological horizon. — Lower Claiborne Eocene. 

 Type. — In Texas State Museum. 

 Leda milamensis nov. sp. PI. 1, fig. 4. 



Specific characterization. — General form as figured; surface covered 

 with fine concentric stria? except near the anterior margin where it 

 is smooth and polished ; diameter from beak to base great and the 

 shell here much inflated; posterior remarkably narrow and flattened. 



Locality. — Smiley 's Bluff, Brazos River, two miles above the 

 mouth of Pond Creek. 



Geological horizon. — Midway Eocene. 



Type specimen. — In Texas State Museum. 



Leda houstonia nov. sp. PL 1, fig. 5. 



Specific characterization. — General form as figured; concentric 

 lines scarcely discernible except where they pass over the umbonal 

 ridge; post-umbonal area traversed by one raised line extending from 

 the umbo to near the extremity of the valve ; sometimes as many as 

 eight or ten raised radiating lines appear near the posterior sub- 

 margin. 



Localities. — Between Orrell's and Evergreen Crossing, Elm Cr. , 

 Lee Co.; Alabama Bluff, Trinity River, Houston Co.; along Elm 

 Cr. from Orrell's to Price's Crossing, Texas. 



Specimens of this species occur in the collection of the Academy 

 of Natural Sciences of Phila., labelled "Leda (Nuculana) subtrigona 

 Con.?, S. Carolina." 



Geological horizon. — Lower Claiborne Eocene. 



Type. — In Texas State Museum. 



Subgenus ADRANA. 

 Adrana aldrichiana nov. sp. PI. 1, fig. 6. 



Specific characterization. — Size and general form as indicated by 

 the figure; exterior smooth and polished; within smooth; sinus 

 small ; posterior row of teeth much the longer. 



The type specimen is compressed vertically, the umbo should be 

 somewhat more elevated than is represented by the figure. The type 

 and all the specimens seen by the writer were in the collection of T. 

 H. Aldrich, temporarily loaned to the survey. 



