1911] Taylor: Mammals of the 1909 Nevada Expedition. 213 



If the species occurs at all in the Pine Forest Mountains, it is 

 certainlj^ onl}- in very limited numbers; but if extinct it has only 

 recently become so. 



Citellus oregonus (C. li. ]\Ierriam). 

 Oregon Ground Squirrel. 



Status. — Comparison of our specimens of the ground scpiirrel 

 of the Pine Forest IMountains with two near topotypes of this 

 species (no. 80507, male, Lost River, Klamath Basin, Oregon, 

 September 23, 1896, E. A. Preble, and no. 80034, male, Lost 

 River, Klamath County, Po Valley, Oregon, August 9, 1896, V. 

 Bailey, loaned by the Bureau of Biological Survey) shows them 

 to be referable to it. Their agreement in coloration is close, 

 although there is no tendency manifested toward any particular 

 concentration of buffy tawny on the nose, as in one of the topo- 

 types (no. 80034). The brown area on the back is perhaps more 

 extensive in some of our specimens than in the topotypes, but 

 the latter ditfer between themselves in this regard. ^Many of our 

 series, two in particular (nos. 8175, 8183), are very much worn. 

 Apparently none have molted. The Oregon animals are sleek and 

 presumably exhibit the fresh fall pelage. Our specimens were 

 all taken from June 29 to eJul^- 22, while the examples from the 

 Klamath Basin were secured in August and September. 



There is a quite noticeable variation in color within our series, 

 some having the sides pale, almost white, and others having them 

 definitely buffy. The same may be said of the underparts. The 

 intensity of chestnut on the lower surface of the tail varies also. 



In size oregonus from the Pine Forest Mountains averages 

 slightly larger than the type specimen of the species from the 

 Klamath Basin (see table of measurements). It is significant 

 of some local variation that the ratio of the length of the tail 

 vertebrae to the total length is considerably more in our series of 

 oregomis than in the type. That the females are larger-bodied 

 than the males is evident ; but the table shows further that the 

 tails and hind feet average shorter in the females than in the 

 males, making the ratio of tail vertebrae and hind foot to total 

 length, respectively, less in the females than in the males. The 



