ABSTRACT 
This report summarizes the available knowledge about the 
mountain beaver, Aplodontia rufa, and lists some 260 litera- 
ture references. Since the first account in 1805, from the 
Lewis and Clark expedition, a considerable literature has 
accumulated, much of which is no longer generally available. 
The mountain beaver, considered the most primitive of living 
rodents, is found only on the Pacific coast of North America. 
Type localities and ranges of the seven races are listed. 

