256 ANNALS OF THE CARNEGIE MUSEUM. 
phragm normal. Inner lamina of inner gills free from abdominal 
sac, except at anterior end. 
Septa and water-tubes well developed. In the female all four gills 
are marsupial, and possess the typical structure. In the basal portion 
of the inner the water-tubes are somewhat wider, but there is hardly 
any difference in their width in the marginal part of the two gills, 
since the water-tubes of the inner gills become narrower by inter- 
calation of additional ones. In the gravid female the gills swell 
moderately, but their edges remain sharp. The eggs form only poorly 
developed placenta in the ovisacs, and the shape of the latter is com- 
pressed and lanceolate (leaf-like). 
The eggs are whitish. I have not seen glochidia, but according to 
Lefevre and Curtis (1910, p. 97, fig. E) they are normal in shape and 
size. Length 0.18; height 0.19 mm. 
Color of soft parts whitish. As usual, the edge of the mantle, 
chiefly along the posterior part, is more or less blackish or brownish. 
Gills paler or darker grayish or brownish white. Foot brownish 
white. The posterior part of the abdominal sac is often suffused with 
black. 
Quadrula sparsa (Lea). 
One male and one sterile female, from the Cumberland River in 
Cumberland and Pulaski Counties, Kentucky, at hand, received from 
B. Walker. . 
Identical in every detail with Q. metanevra, to which it is also allied 
by the shell. The agreement extends so far, that minor details are 
also identical, as the smooth edge of the anal, the shape of the palpi, 
and the black pigment of the posterior part of the abdominal sac. 
In the male supra-anal and anal were not separated, but this region 
was somewhat injured, so that the mantle-connection may have been 
torn. 
Charged marsupia and glochidia unknown. 
Quadrula cylindrica (Say). 
Nine specimens (males and females) from the Ohio drainage of 
western Pennsylvania have been examined in the laboratory, and 
several more in the field, taken from the Ohio River in western Penn- 
sylvania and Ohio. Two males were received from H. E. Wheeler, 
from the Ouachita in Arkansas. ' 
