go6 QUADRULA 
Margarcn (Unio) graniferus Lea, Syn., 1852, p. 22; 1870, p. 
34- 
Quadrula granifera SIMPSON, Syn., T900, p. 795. 
Smaller, more inflated, usually brighter, higher in propor- 
tion to length, with stronger tubercles, more coppery nacre 
and a less remote pallial line than tuberculate. The young of 
that species are compressed as are the adults. 
Var. pusilla Simpson. 
Much smaller than the type, with an angled posterior ridge, 
which ends in a point; posterior furrow deeper than in the 
type; epidermis less smooth. 
Length 34, height 32, diam. 22 mm. 
Type locality, Green River, Ky. 
Quadrula granifera var. pusilla SIMPSON, Syn., 1900, p. 795. 
Were it not for the fact that a dwarf form of Cyprogenia 
irrorata was found with this form, I should be inclined to give 
it specific rank. It is more elongated than the granifera and 
the tubercles are sharper. | 
Group of Ouadrula ostreata. 
Shell rhomboid, incurved on the base, with a well-developed 
posterior ridge, somewhat biangulate behind; beak sculpture 
consisting of a number of fine, concentric ridges showing a 
tendency to be doubly looped, which gradually change, first to 
corrugations and then to pustules; pseudocardinals ragged; 
secondary lateral of right valve but slightly developed. 
Animal unknown. 
QUADRULA OSTREATA (Morelet). 
Shell subtriangular, inequilateral to subequilateral, some- 
what inflated, solid in front, thinner behind, with a very high 
umbonal region, the beaks curved inward and forward: beak 
sculpture faint, consisting of slight doubly-looped ridges ; pos- 
terior ridge well developed, double, the lower ridge strong and 
angular; base rounded, incurved behind in old shells; surface 
covered with rather strong, irreguiar, concentric ridges and 
