ORTMANN: FAMILIES AND GENERA OF NAJADES. 3859 
again at about the middle of the lower margin. The inner edge has 
crowded, very fine papilla, which decrease anteriorly, and the anterior 
part of the edge is smooth. The space between the two edges is 
of a peculiar spongy structure, full of what appear as finely rounded 
or elongated pores. 
In the male the two edges of the mantle are subparallel and close 
together, as usual, and the inner one has very minute papillae. 
The color of the soft parts is generally whitish or yellowish white. 
Outer edge of mantle grayish posteriorly, in the region of the anal and 
supra-anal blackish, not spotted. Papille of branchial brown, but 
this color does not run forward along the inner edge, and the inner 
edge itself and the spongy space between the two edges is snow-white. 
Truncilla florentina (Lea). 
One gravid female has been received from B. Walker. It is from 
Shoals Creek, Lauderdale Co., Alabama, collected Nov. 2, 1909, by 
Pie Li Simith. 
Soft parts practically identical with those of T. rangiana, but the 
color of the margin of the mantle is different. Here both edges of the 
mantle are black-brown all around, and the space between the two edges 
is deep black. There is also in this region a deep black streak on the 
inside of the inner edge. The outer edge is slightly scalloped, cor- 
responding to the dentate margin of the shell. In the specimen at 
hand, the spongy space is covered with numerous low granules, which 
I do not see in T. rangiana. 
Glochidia like those of the other species; length 0.23; height 0.22 
mm, (see Plate XX, fig. 12). 
In this species also the post-basal expansion is somewhat different 
in texture from the rest of the shell, contrary to Walker’s statement. 
It resembles very closely the structure seen in T. capseformis. 
Truncilla capseformis (Lea). 
One male and one sterile female, received from B. Walker, from the 
South Fork of Cumberland River, Burnside, Pulaski Co., Kentucky, 
are at hand. 
Soft parts essentially those of 7. rangiana and florentina, and in 
color agreeing with those of T. florentina, although the streak of 
pigment on the inside of the inner edge of the mantle is absent. There 
are also low granules upon the spongy space, but they are finer 
