ORTMANN: FAMILIES AND GENERA OF NAJADES. 345 
and Simpson (in Baker, 1898, p. 102), and a figure of them has been 
published by Lefevre and Curtis (1910, pl. 1, fig. 5). 
The inner edge of the mantle of the female in front of the branchial 
has (see Ortmann, 1911), p. 318) a row of regular, rather crowded, 
subequal papilla, which are large and conical, and run forward to 
about the middle of the ventral margin, where they disappear sud- 
denly. The anterior part of the inner edge is smooth. The papille 
increase somewhat in size from the branchial forward, and the largest 
papilla stand near the anterior end of the row. A distinct brownish 
black streak accompanies this row, and the papillae have the same 
color at their bases, while they are whitish at their tips. 
Marsupium occupying less than the half of the posterior section of 
the outer gill, with a very small non-marsupial section behind. Ovi- 
sacs fifteen to thirty, without black pigment at their ends. Glochidia 
(Lea, Obs., VI, 1858, pl. 5, fig. 11; Lefevre and Curtis, 1910, p. 97, 
fig. L; Ortmann, 19110, pl. 89, fig. 21) as in the preceding species; I 
have found their length to be 0.22; height 0.28 mm.; while Lefevre 
and Curtis give length 0.20; height 0.24 mm. 
In other respects like the last species, but inner lamina of inner gills 
always entirely connected, and mantle-connection between anal 
and supra-anal shorter than anal. 
Genus LAmpsILis Rafinesque. (1820.) 
(Simpson, 1900), p. 526 (restricted).) 
Shell ovate to elliptical, or elongated. Outside of shell not sculp- 
tured. Beak-sculpture of the sinuated or double-looped type, finer 
or coarser, sometimes the posterior loop open behind, or the sculpture 
is obsolete. Epidermis generally yellowish or greenish, mostly rayed, 
often very beautifully so. Female shell quite distinct from that 
of the male, with a strong inflation and dilatation in the post-basal 
region, producing a distinct posterior truncation of the shell. 
Inner lamina of inner gills entirely connected with abdominal sac, 
but sometimes a small hole is left at the posterior end of the foot. 
In the female, the edge of the mantle in front of the branchial is 
developed into a ribbon-like flap, generally produced anteriorly into 
a free, projecting lobe, which has a lacerated appearance. Along the 
edge of the flap, there may or may not be crenulations or teeth, but 
never real papilla. On the inside, the flap is beautifully colored, 
