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U. S. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



doubt whatever that, with very few exceptions, the many species described by Audubon and 

 Bachman as from California are really from Southern Mexico, adjacent, perhaps, to southern 

 California, and have no right to a place in a fauna of North America, certainly not of the 

 United States. 



Detailed measurements of a specimen in alcohol. 



List of specimens. 



SCIUEUS CASTANONOTUS, Baird. 



Chestnut Backed Squirrel. 



Sciurus castanotus, BAIRD, Pr. A. N. Sc. Phila. VII, April, 1855, 332. (Typographical error for castanonotus.) 



Body about 11 inches. Tail, with the hairs, but little longer. Hind feet 2.60 inches, skull, 2.40. 



Size about that of ^. cinereus. Five permanent molars in the upper jaw. Tail about equal in length to the body, not 

 bushy. Ears with rather short hairs, not tufted. Soles naked in winter. Back deep chestnut brown ; rest of upper parts 

 mixed ash, gray, and lead color. Eyelids, upper surfaces of feet, and whole under parts white. Ears and sides of head 

 ash gray. The sides, tip, and under parts of tail, pure white ; above (within the margin) mixed black and white. 



A detailed description of this squirrel will be found in the report of the Zoology of the United States and Mexican 

 Boundary Survey. 



This species bears a very close resemblance to S. aberti and may prove to be the same, 

 although there are abundant differences. The most striking characteristic is the absence of the 

 beautiful ear tufts of S. aberti. Some of our squirrels which have smooth ears in summer are tufted 

 in winter, but as the Coppermines specimens were caught in winter, it is not likely that they are 

 ever tufted. The tufts, too, of S. aberti are long hairs growing from the very margins of the 

 ears and projecting an inch beyond. The convexity of the ear and a woolly space at their 



