340 



BULLETIN 56, I'NITED STATES NATIONAL MUSEUM. 



Seasonal changes. There are l\\<> seasonal pelages, winter and 

 summer, the hitter worn only for a few weeks. The winter overhair 

 fulls out at the beginning of hot weather, leaving the animal clad in 

 its winter underfur, which soon becomes brittle and worn, exposing 

 the dark color at base, when the animal looks ragged and patchy, 

 often appearing to he blackish when seen at a distance. The summer 



Fig. 56. -Cynomys ludoviciantjs.arizonensis. (Cat. No. 36362, U.S.N. M.) a, Dorsal view; 

 b, Ventral view; e, Lateral view. 



pelage is first acquired on the forefeet and head, extends slowly hack- 

 ward over the shoulders, but rapidly over the ventral surface and 

 inner sides of the hind limbs, then to their outer surface, and lastly 

 to the rump and tail. The underfur disappears at the advenl of the 

 coarse summer coat, in which it is wanting. The change from winter 

 to summer dress is a slow one. that from summer to winter much 



