30 Proceedings of the Biological Society of Washington. 



Remarks. — From typical nanus the present form may be readily distin- 

 guished by larger size, and heavier, deeper skull, although its short tail 

 and gray coloration at first suggest that species. The skulls, however, 

 show the connection to be with montanus and not with nanus. 



Specimens examined. — In all, 21, from the following localities in 

 Wyoming: 



Milford, 4; Sage Creek (near Milford), I ; Lone Tree, Uinta County, 

 1; Cumberland, 5; Cokeville, 2; Border, 7; Afton, I (too young for 

 positive identification). 



