ORTMANN: FAMILIES AND GENERA OF NAJADES. 251 
(rarely smooth), which are irregularly scattered, and have no connec- 
tion with the beak-sculpture. Beak-sculpture poorly developed, 
simply concentric. 
QO. pustulosa, spherica, refulgens, mortont. 
2. Lachrymosa-group. 
Shell subquadrate or subtrapezoidal, sometimes somewhat elongate. 
Generally profusely sculptured upon the disk with tubercles, pustules, 
and ridges of a more definite arrangement. This sculpture is contin- 
uous with the beak-sculpture, which is quite distinct, and of the double- 
looped type. Shell with a rather distinct, but narrow, posterior 
ridge and in front of this flattened, or with a broad and shallow de- 
pression. Epidermis rayed, rays not broken, but irregular, and with 
the tendency to spread over the epidermis. 
Q. lachrymosa, aspera, tuberculata. 
3. Metanevra-group. 
Shell subquadrate, or subtrapezoidal, sometimes quite elongated. 
Surface generally sculptured with tubercles and pustules of a more or 
less distinct arrangement, the sculpture continuous with the beak- 
sculpture, which is of the double-looped or zig-zag type. Shell with a 
distinct, broad, and high posterior ridge, depressed in front of this, 
but without distinct and broad radial furrow. Epidermis rayed, rays 
broken up into characteristic triangular spots. 
Q. metanevra, sparsa, cylindrica. 
Quadrula pustulosa (Lea). 
I have investigated about half a dozen specimens from the Ohio 
drainage in western Pennsylvania, West Virginia, and Ohio, and (var. 
schoolcraftensis Lea) from Lake Erie in Ohio. Further I had ten 
specimens, males and females, from Ouachita River, Arkadelphia, 
Clark Co., Arkansas (H. E. Wheeler). Both males and females were 
seen, but none of the latter gravid. ; 
The soft parts have been described by Simpson (in Baker, 1898, 
p. 87). 
Anatomy similar to that of the genera Fusconaja and Crenodonta, 
chiefly the latter. Anal and supra-anal separated by a short mantle- 
connection. I never found the latter absent. Branchial opening 
with papilla, anal crenulated. Palpi of the usual shape, their poste- 
rior margins connected for about one-third of their length. 
Gills short and broad (according to shape of shell), the inner gill 
