856 QUADRULA 
QUADRULA PUSTULATA (Lea). 
Shell subqauadrate, inflated, slightly inequilateral, solid; 
beaks high and full, turned forward over a lunule, their sculp- 
ture a few coarse, irregular corrugations; posterior ridge well 
developed, narrowly rounded or subangular, sometimes in- 
clined to be double below; anterior end rounded, sometimes 
feebly angled above; base line slightly curved; posterior end 
almost squarely truncated, sinused in the middle at the termi- 
nation of a radial depression above the posterior ridge; surface 
with a few large warts or pustules, often arranged in two im- 
perfect rows, one on the posterior ridge, the other some dis- 
tance in front of it; epidermis generally smooth, subshining, 
ashy-green in young shells, rarely feebly rayed, ashy-brown in 
old shells; pseudocardinals considerably split up; lateral of the 
right valve single or double; beak cavities deep, compressed ; 
anterior scars small, deep; nacre white, iridescent behind. 
Length 60, height 53, diam. 33 mm. 
Ohio, Cumberland, and Tennessee River systems; Mississip- 
pi River and tributaries from eastern Iowa south to Louisiana. 
Type locality, Ohio; Tennessee. 
Unio pustulatus Lea, Tr. Am. Phil. Soc., IV, 1834, p. 79, pl. 
vil, fig. 9; Obs., 1, 1834, p. 89, pl. vi1, ig. 9 —HANtEy,, Biv. 
Shells, 1843, p. 178, pl. xxu, fig. 36—CueEnu, Ill. Conch., 
1858, pl. xv, figs. 8, 8a, 8b. 
Margarita (Unio) pustulatus Lua, Syn., 1836, p. 15; 1838, p- 
se 
Margaron (Unio) pustulatus Lea, Syn., 1852, p. 22; 1870, p. 
33- 
Ouadrula pustulata Stwpson, Syn., 1900, p. 782. 
Unio nodulatus Say, Am. Conch., VI, 1834.—Conrap, Monog., 
1837, p. 80, pl. xiv. fig. 1.—Kustrer, Conch. Cab., 1861, p. 
264, pl. Lxxxvi, fig. 1—Rerxrve, Conch. Icon., XVI, 1864, pl. 
MITT SS 
Unio nodulatus RAFinKsouE var. pustulatus Pate, Conch. 
Sam., LDL, 18¢0, pp. 16%: 
