﻿r.AMPSiijs 95 



color of certain specimens of that species from Michigan, but 

 it is shorter, less solid and inflated than that species, and has a 

 larg-e, dark blotch on the central and upper part of the shell. 



Lampsilis recta (Lamarck). 



Shell large, elongated, dorsal and ventral lines nearly paral- 

 lel, solid, inflated, rounded in front, pointed behind ; with full 

 but rather low beaks, whose sculpture consists of faint, delicate 

 ridges, scarcely doubly looped ; posterior ridge rather low, 

 rounded; ligament long; surface faintly and irregularly, con- 

 centrically sculptured, varying from black to olive-green, gen- 

 erally lighter colored in the umbonal region, the young and 

 sometimes older shells often faintly rayed, left valve with two 

 nearly equal, ragged, erect pseudocardinals and two long, 

 slightly curved laterals ; right valve with one pseudocardinal, a 

 feeble, compressed one above it, and one lateral with a vestige 

 of a second below it ; muscle scars well impressed, smooth ; beak 

 cavities shallow, with two or three deep dorsal scars; nacre 

 purple or bluish-white, often whitish, with a purple flush at the 

 beak cavities. The male shell is drawn out behind and ends 

 in a blunt point about midway up from the base ; the female 

 shell has a long, rounded marsupial swelling and ends in a 

 more blunt point two-thirds oi the way up from the base. 

 Length 150, height 65, diam. 45 mm. 



Entire Mississippi drainage; Alabama River drainage; Red 

 River of the North ; St. Lawrence system. 



Type locality. Lake Erie. 

 Unio recta Lamarck, An. sans Vert., VI, 18 19, p. 74. — Val- 

 enciennes, Rec. Obs. Zool., II, 1833, p. 234, pi. uv, fig. i. 

 Unio fIJgtwna) recta Swainson, Treat, on Mai., 1840, pp. 



267, 274, fig. 55. 

 Eurynia (Eurynia) recta Ortmann, Am. Car. Mus., VIII, 



191 2, p. 344, fig. 24. 

 Unio rectus Conrad, Monog., IIL 1836, p. 33, pi. xv,— Potiez 

 and MiCHAUD, Gall. Moll., 1844, II, p. 149. pl- Lvn, f^gs. 3, 4- 

 — KusTER, Couch. Cab. Unio, 1852, p. 35, pi. vi, fig. i ; ph 

 VII, fig. I.— Chenu, Man., 1859, II, p. i39- f^S- 675.— Reeve, 

 Conch. Icon., XVI, 1865, pi. xix, fig. 86.— Call, Tr. Ac. 

 Sci. St. Louis, VII, 1895, p. 43, pi. VII. 



