954 The American Naturalist. — [November, 
Amnicola sayana Anthony, Cross Lake at Shreveport. Not 
very abundant. 
UNIONID X. 
UNIO. 
Unio anodontoides Lea, is extremely abundant in many of the 
bayous and lakes. It was collected in Cross Lake, Caddo 
Lake, Red River at Shreveport, Lake Bisteneau, Corney Bayou, 
Bayou Pierre, etc. It was found most abundantly in Lake 
Bisteneau, the species from Red River at Shreveport were the 
most perfect. Although this species exhibits some variation in 
size and relative thickness of the shell, the variation is rather 
slight when compared to the great amount of some other 
species. 
Unio gracilis Barnes, is not very abundant. In Caddo Lake 
a fine lot of young specimens were collected. It was also 
found in Cross Lake, Red River (at Shreveport), Dorcheat 
Bayou, Corney Bayou, Bayou Pierre, and Lake Bisteneau. 
nio purpuratus Lam. This handsome Unio is rather abund- 
ant. It was collected in Cypress Bayou (Texas), Caddo Lake, 
Cross Lake, Corney Bayou, Dorcheat Bayou, Bayou Pierre and 
Lake Bisteneau. The most perfect specimens were in Caddo 
Lake; here a considerable number of perfect young were ob- 
tained. The largest specimen wasa dead valve from Dorcheat 
Bayou, it being about six inches in length. A large number 
of specimens were collected from little pockets that had been 
formed alongside Corney Bayou. The characters of this spe- 
cies are very constant. DAT 
Unio levissimus Lea, Caddo Lake, Red River at Shreveport. 
Rather rare. Some beautiful young were obtained in Caddo 
Lake. (ees 
Unio migerrinus Lea. Localities: Corney Bayou, Cypress 
Bayou, La., Dorcheat Bayou and creek near Rosefield. This 
species is rather abundant. The largest specimens were ob- 
tained from Dorcheat Bayou, where the shells, besides being 
larger than those of the neighboring streams, have thick, some- 
what massive, shells. 
Unio haleianus Lea. A single specimen was collected by Mr. 
O. B. Lewis, at Burk Place, in a small creek. I collected a 
