﻿42 F.AMI'SIMS 



curve, rounded in front of the beaks and out behind them; 

 two pseudocardinals in the left valve, one behind the other, 

 the anterior much the larger, with a triangular outline, both 

 are com])ressed and situated in front of the beak ; there are 

 two small renx)te laterals and the middle of the hinge plate 

 is narrow and rounded ; right valve with two subconipressed, 

 triangular pseudocardinals, the lower the larger, and one 

 high lateral truncated behind ; beak cavities deep and wide ; 

 muscle scars shallow, smooth ; nacre white. The female shell 

 is somewhat inflated at the post-basal outline ; it is not so sharp 

 ,at the posterior end as is the male shell. In the male shell the 

 posterior point is about one half the distance up from the base 

 to the top ; in the female it is a little higher. 



Length 85, height 65, diam. 50 mm. 



Tombigbee and Alabama River drainage. 



Type locality, Othcalooga Creek, Ga. 

 Unio excavatiis Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 2,2; 



Jl. Ac. N. Sci. Phila., IV, 1858, p. 71, pi. xiii, fig. 52; Obs., 



VI, 1858, p. 71, pi. xiii, fig. 52.— Chenu, Man., 1859, II, 



p. 138, fig. 665. — SowEKBY, Conch. Icon., XVI, 1868, pi. 



i.xxvii, fig. 403. 

 Margaron (Unto) excazatiis Lea. vSyn., 1870. p. ^y. 

 Lampsilis excaz'atus Simpson, Syn., 1900, p. 528. 

 ? Unio 02'atns Say var. omatus Conrad, Monog., I, 1835, p. 4. 

 Unio ornatus Sowerby, Conch. kx)n.. XVI, 1866, pi. xxxi, fig. 



162. 



Lampsilis binominata (Simpson). 



Shell of moderate size, subsolid to rather thin, somewhat 

 inflated, the male irregularly elliptical, the female obovate ; 

 posterior ridge not high, rounded ; beaks only moderately full ; 

 their sculpture consisting of strong, slightly double-looped 

 ridges : epidermis smooth, shining, showing the rest periods, 

 wrinkled on the posterior slope, greenish, yellowish-green or 

 tawny, showing a few narrow, generally sharply defined dark 

 green rays ; the teeth are much as in L. e.vcazata, two com- 

 pressed pseudocardinals in each valve, two laterals in the left 



