﻿128 LAMI'Sir.IS 



Laau'Siuis Ki,i.ii'Sii'OKMis (Conrad). 



Shell long elliptical or long ovate, subinflated, generally quite 

 solid, sometimes very heavy, with a moderately rounded pos- 

 terior ridge; beaks low, often tlattened, lunuie elongated, pass- 

 ing back under the beaks ; anterior end rounded ; posterior end 

 drawn out to a dull, rounded or biangulate point about midway 

 up from the base; base Hue rounded, often a little fuller just 

 behind the middle, and between this and the post-point the out- 

 line is sometimes a little incurved; surface with rude, irregular 

 growth lines, greenish-yellow, or yellowish-green with numer- 

 ous wavy, faint rays, often showing feeble, concentric bands 

 or clouds of green. Jn front of the posterior ridge there are 

 frequently deep, irregular, radiating grooves and sometimes 

 finer and more regular radiating ones ; epidermis often cloth- 

 like, lusterless. There is little difference between the male and 

 female shell, the latter being a trifle more produced behind the 

 center of the base; pseudocardinals two in the left valve and 

 one and a vestige of a second in the right, small, stumpy ; lat- 

 erals short, rather heavy ; muscle scars deep ; beak cavities very 

 shallow, with a few pits; nacre bluish-white or flesh-colored, 

 thicker in front, with a posterior, radial furrow. 



Length 72, height 42, diam. 28 mm. 



Length 85, height 45, diam. 34 mm. 



Upper Mississippi Valley generally ; south to about latitude 

 38" ; western New York ; southern Michigan ; southern Can- 

 ada ; Red River of the North. 



Type locality, Michigan. 

 Unio ellipsiformis Conrad, Monog.. VIIT, 1836, p. 60, pi. 



XXXIV, fig. I. 

 Lampsilis ellipsiformis Simpson, Syn., 1900, p. 557. 

 Unio spatulatus Lea, Pr. Am. Phil. Soc, l\\ 1845, P- 164; Tr. 



Am. Phil. Soc, X, 1848, p. 80, pi. viii. fig. 22 ; Obs., IV, 1848, 



p. 54, pi. VIII, fig. 22. — KusTET?, Conch. Cab. L^nio, i86r, p. 



261. pi. LXXXVII, fig. 7. 

 Margaron (Unio) spatulatus Lea, Syn., 1852, p. 28; 1870, p. 



43- 

 Lampsilis spatulatus Baker, Moll, Chicago, Pt. L 1898. p. 106, 



pi. X, fig. 5 ; XIII, fig. 2. 



