1922] Swarth: Birds and Mammals of the Stikine Begion 169 



chipmunks and ground squirrels. This, I believe, is kn unusual action 

 for a Peromyscus. At the same place an adult female was trapped 

 that had lost one hind leg at the knee and all of the tail. These muti- 

 lations were evidently of long standing and the animal was in good 

 condition otherwise.. It may be doubted, however, whether it could 

 have survived them in other surroundings ; the old cabins here occupied 

 by the mice probably afforded exceptional shelter from many dangers. 



h (M « 



borealis 



macrorkinus 



5 



Pig. T. Diagram showing individual and geographic variation in ratio of 

 length of tail vertebrae to total length in adult white-footed mice (both sexes). 

 Figures at left of the vertical lines indicate numbers of specimens measured, 

 length of lines shows range of individual variation; points connected by lines 

 mark positions of averages. 



