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U. 8. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



A young specimen from Fort Reading is rather darker than usual on the back, and may 

 possibly belong to S. douglassii. On account of the locality, however, I have entered it among 

 the present species. 



The reception of many additional specimens, since the preceding description was written, 

 substantiate the permanence of character as given above in the California animal, and as dis 

 tinguished from the S. douglassii. These vary in the amount of hoary on the shoulders, but 

 in none is the back darker than the ground color, and unbroken by mottling. The soles vary 

 from entirely naked in summer skins, except immediately at the heel, to-densely hairy to the 

 tubercles in winter ones. Only in the latitude of San Diego do the soles appear to remain nearly 

 naked throughout the year. 



This species was not recognized by Audubon and Bachman as any thing more than a variety 

 of Spermophilus douglassii. Even should this be the case, its name must take precedence of the 

 last named species, on account of having been published first in the pages of the Faana 

 Boreali-Americana. 



This is the animal so well known in California, under the name of ground squirrel, as 

 causing so much damage to the farmer by the depredations it commits on grain fields and, in 

 fact, almost every agricultural product, as well as by the disturbances of the soil by its excava 

 tions. 



List of specimens. 



