﻿LAMPSIIJS 8l 



Unio gratis P^tel, Conch. Sam., Ill, 1890, p. 154. 



Unio luteohts Sovverby, Conch. Icon., XVI, 1867, pi. lviii, 



fig. 293a. 

 Unio delodontus Sowerby, Conch. Icon., XVI, 1867, pi. lvii, 



fig. 288. 

 Unio crassidens Sowerby, Conch. Icon., XVI, 1868, pi. exii, 



fig. 312. 

 Unio pictus Sowerby. Conch. Icon., XVI, 1868, pi. exii, fig. 



313- 

 Unio venu-stus Sowerby, Conch. Icon., XVI, 1868, pi. lxiv, 



fig. 326. 

 Unio upsoni Marsh, Conch., Ex. i, 1887, p. 51. 

 Unio pinguis Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. 84 ; Jl. Ac. 



N. Sci. Phila., IV, 1858, p. 78, pi. XV, fig. 58 ; Obs., VI, 1858, 



p. 78, pi.. XV, fig. 58. 

 Mar gar on (Unio) pinguis Lea, Syn., 1870, p. 44. 

 Lampsilis pinguis Simpson, Syn. 1900, p. 540. 



After again carefully comparing the type of Lea's Unio 

 pinguis, the only specimen I have ever seen, I am quite certain 

 that it is a somewhat peculiar shell of L. ligamentina, in which 

 the hinge line is a little injured, so that it has become sinuous. 

 The following is a description of the type : 



Shell irregularly obovate, rather solid, inflated, with a low, 

 rounded posterior ridge ; ligament large and long, brownish ; 

 beaks rather full, turned slightly forward ; in front of and be- 

 between them there is a wide, deep lunule ; surface having occa- 

 sional, irregular, low, concentric ridges, yellowish-green with 

 a few pale rays ; hinge line decidedly sinous ; left valve with 

 two sharp, somewhat ragged pseudocardinals and two 

 lamellar laterals ; right valve with two opposite pseudocar- 

 dinals, the upper the smaller, and ®ne high lateral ; beak 

 cavities rather deep ; anterior scars deep, separate ; posterior 

 scars shallow ; nacre whitish, iridescent behind with lurid 

 blotches in the cavity of the shell, scarcely thickened before. 



Length 70, height 48, diam. 2tZ m^n. 



The shell 'gapes decidedly at the anterior base, and the de- 

 pressed lunule makes a deep impression on the dorsal outline. 



