842 QUADRULA 
Iintire Mississippi river drainage; various localities in the 
St. Lawrence basin; Red River of the North; southwest into 
eastern Texas. 
Type locality, Ohio. 
Unio lachrymosus Lea, Tr. Am. Phil. Soc., III, 1828, p. 272, 
pl. v1, fig. 8; Obs., I, 1834, p. 14, pl. vi, fig. 8 —Han ey, Biv 
Shells, 1843, p. 177, pl. xx, fig. 38.—Kuster, Conch. Cab., 
1854, p. 70, pl. xv, fig. 3—CneEnu, Ill. Conch., 1858, pl. 
xv, figs. 6, 6a, 6b; Manual 1849, II, p. 142, fig. 698.— REEVE, 
Conchs Icon: 20V, 1864, pl nie tie 333? 
Margarita (Unio) lachrymosus Lea, Syn., 1836, p. 14; 1838, 
De 15: 
Margaron (Unio) lachrymosus Lea, Syn., 1852, p. 21; 1870, 
pase: 
Quadrula lachrymosa BAKER, Moll. Chicago, Pt. I, 1808, p. 83, 
pl. xxv, fig. 1; xu, fig. 2—SIMPSON, Syn., 1900, p. 776. 
Unio asperrimus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 71, pl- 
v, fig. 3; Obs., I, 1834, p. 81, pl. v, fig. 3—-HANLEy, Biv. 
Shells, 1843, p. 178, pl. xx1, fig. 12—Potigz and MicHaAup, 
Gall. Moll., 1844, p. 156, pl. tix, figs. 2, 3—CuHeEnu, III. 
Conch., 1858, plo 1x, figs. ©, ta, vb. 
Margarita (Unio) asperrimus LEA, Syn., 1836, p. 14; 1838, p. 
WS: 
Margaron (Unie) asperrimus Lea, Syn., 1852, p. 21; 1870, p. 
33. 
Unio quadrulus Say, Am. Conch., VI, 1834.—KustrEr, Conch. 
Cab., 1861, p7184, plivin, tie. 1: 
Unio quadratus REEVE, Conch. Icon., XVI, 1864, pl. vr, fig. 24. 
Abundant, widespread and variable. Specimens occur, 
which are almost without tubercles, others are almost entirely 
covered with them. Those on the central ridges are often 
elongated in the direction of the growth lines, while the ones 
on the posterior ridge are rounded. 
QUADRULA COUCHIANA (Lea). 
Shell of medium or rather small size, subrhomboid, subin- | 
flated, rather solid, slightly inequilateral; beaks full and ele- 
vated, their sculpture consisting of strong doubly-looped or 
