126 Bulletin American Museum of Natural History.  [Vol. XXXIV. 
Unio leanus Meek. 
I take occasion to note that this name is not really preoccupied, the recent 
species being U. leat. Consequently the name U. meekiz White is not re- 
quired. I have examined cotype material in the National Museum, from 
Church Buttes, Wyoming. It is a heavy species with large teeth, repre- 
sented by five internal casts and one fragmentary shell, which is very thick. 
The sculpture cannot be made out. 
A species represented by casts in bright green rock from the Bridger Beds 
at Fort Bridger, Wyo. (Amer. Mus. N. H. Exp., 1893) may be compared 
with U. leanus, but is evidently distinct. It is not in a condition for de- 
scription. 
