Prace,  XoorEx 
Unio endlichi White. Laramie group of the Cretaceous series. 
Fic. 1. Right side view of a large specimen. 
Fic. 2. Interior view of a smaller, left valve. 
Unio propheticus White. Laramie group of the Cretacéous. series. 
Fic. 3. Left side view. 
Unio primevus White. Judith River beds of the Cretaceous series. 
Fic. 4. Left side view of a broken specimen. 
Unio brachyopisthus White. Laramie group of the Cretaceous series. 
Fic. 5. Right side view of a small, probably a young, specimen. 
Fic. 6. Front view of the same. 
