848 QUADRULA 
Unio rumphianus Lea, Tr. Am. Phil. Soc., X, 1852, p. 276, pl. 
xxi, fig) 347 Obs. .V; 2852) pa 32s plex, ie ae 
Margaron (Unio) rumphianus Lea, Syn., 1852, p. 21; 1870, p. 
33: 
Quadrula rumphiana SIMPSON, Syn., 1900, p. 778. 
Unio blandianus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 
203; Jl Ac ON. Set. Phila. TV, 1858) p65, cpiexiaioael ye 
Obs., VI, 1858, p. 65, pl. x1, fig. 47—Sowerry, Conch. Icon., 
XVI, 1868, pl. Lxxvitl, fig. 405. 
Margaron (Unio) blandianus Lea, Syn., 1870, p. 33. 
A very fine species with generally smooth, somewhat round- 
ed posterior ridge and rich shining brown epidermis. The 
nacre is fine and silvery. I have seen specimens, which I re- 
ferred to this species with doubt, that have quite strong, rough 
pustules. 
Group of Quadrula pustulosa. 
Shell round quadrate, truncated behind, full and angled 
back of the ligament; beaks high; beak sculpture a few coarse 
ridges, which are swollen at the posterior ridge, which is 
rounded; surface generally more or less pustulous, but some- 
times entirely smooth, and in some cases slightly corrugated ; 
epidermis often having broad, faint, green rays; hinge strong ; 
nacre white or purple. 
Animal with the marsupium occupying all four gills 
throughout; inner gills the larger, free the whole or the 
greater part of their length from the abdominal sac ; branchial 
opening having clustered, often branching papille. 
QUADRULA PUSTULOSA (Lea). 
Shell subquadrate, subrhomboid, subtriangular or suborbic- 
ular, generally inflated, solid, inequilateral; beaks full and 
high, turned forward over a deep lunule, their sculpture a few 
coarse corrugations; anterior end rounded; base straight or 
lightly curved; posterior end squarely or obliquely truncated, 
usually well-angled behind the ligament; posterior ridge only 
moderately developed, rounded; there is often a slight radial 
