340 



BULLETIN r,6, UNITED STATES NATIONAL MUSEUM. 



Seasonal chang<'f<. — There are two .searsoiml pelages, winter and 

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

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

 its Avinter underfur. which soon becomes brittle and worn, exposing 

 the dark color at ]>ase, when the animal looks ragged and patchy, 

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



r)6.— CVNOMYS UDOVICIANUS ARIZONENSIS. (CAT. N<l. ;-i63(i'_'. T.S.N.M.) «, DoRSAI, VIEW; 



/). Ventral view; <■, Lateral view. 



pelage is tirst acquired on the forefeet and head, extends slowly }>ack- 

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

 inner sides of the hind lim})s, then to their outer surface, and lastly 

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

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

 to sunnner dress is a slow one, that from sunmier to winter much 



