854 QUADRULA 
Unio mortoni Conrap, Monog., II, 1836, p. 11, pl. vr, fig. 1— 
Kuster, Conch. Cab. Unio, 1852, p. 51, pl. x1, fig. 1. 
Quadrula mortont SIMPSON, Syn., 1900, p. 781. 
Unio turgidus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 11, pl. v, 
fig. 11; Obs., II, 1838, p. 11, pl. v, fig. 11—Hanuey, Biv. 
Shells, 1843, p. 180, pl. xx1, fig. 51.—CHENU, III. Conch., 
1950; Pl. KV, a1oSa ly haope 
Margarita (Unio) turgidus Lea, Syn., 1836, p. 16; 1838, p. 15. 
Margaron (Unio) turgidus Lea, Syn., 1852, p. 22; 1870, p. 34. 
Varies greatly in the degree of smoothness. Some shells 
have scarcely a nodule; in others they are crowded over the 
whole surface. ‘The pustules are often compressed, sometimes 
into short ridges and some of them are laid on obliquely to 
the growth lines. . 
QUADRULA SPH&RICA (Lea). 
Shell subquadrate or suborbicular, inflated, solid, slightly 
inequilateral; beaks full and high, turned forward over a 
lunule; posterior ridge moderately developed, subangular ; an- 
terior end rounded or slightly subtruncate above; base round- 
ed: posterior end almost squarely truncated; posterior three- 
fifths of the surface somewhat nodulous, the nodules generally 
rather feeble; epidermis reddish-chestnut, subshining ; pseudo- 
cardinals irregular, somewhat torn and ragged; laterals short, 
that of the right valve single or double; beak cavities deep, 
compressed; muscle scars deep; nacre brilliant purplish or 
violet, richly and darkly iridescent behind. 
Length 48, height 48, diam. 35 mm. 
Streams of Alabama and Mississippi flowing into the Gulf 
of Mexico. 
Type locality, Pearl River, Jackson, Miss. 
Unio sphericus Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 145; 
jl. Ac. N. Sei. Phila., 1860; p: 310; pl. 11, fe 132;9@bs, Son, 
1860, p. 79, pl: El) fig. 132: 
Margaron (Unio) sphericus Lea, Syn., 1870, p. 33- 
Ouadrula spherica SIMPSON, Syn., 1900, p. 781. 
