VOL. XI, PP. 67-68 APRIL 21, 1897 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



DESCRIPTION OF A NEW VOLE FROM OREGON. 

 BY GERRIT S. MILLER, JR. 



A small species of Microtus of the nanus group, represented by 

 twelve specimens from the Willamette Valley, Oregon,* may be 

 named and described as follows : 



Microtus canicaudus sp. nov. 



Type from McCoy, Oregon. Adult J\ No. 75841, U. S. National Museum, 

 Biological Survey collection. Collected December 1, 1895, by B. J. Breth- 

 erton. Original No. 2119. 



General characters. Size and proportions about as in Microtus nanus 

 (Merriam), but color yellower and less gri/zled, and tail usually nearly 

 uniform grayish above and below ; skull broader than in M. nanus, with 

 rounder audital bullse and differently shaped bony palate. 



Color. Head, back, and sides umber-brown thickly sprinkled with 

 blackish hairs, the ground color darker on head and paler on sides, where 

 it shades rather abruptly into color of belly ; ventral surface grayish 

 white, faintly marked with yellowish; fur everywhere deep plumbeous 

 at base, this color showing through irregularly on belly and throat; tail 

 whitish gray, slightly paler below and darker at tip. 



The exact shade of brown varies, but it is always yellower than in 

 M. nanus, and seldom shows any approach to the peculiar grizzled ap 

 pearance characteristic of the latter. The tail occasionally has a toler 

 ably well-defined dark dorsal stripe, but in the great majority of speci 

 mens (taken in March, April, October, November, and December) it is 

 scarcely visible. 



*Two from Beaverton (Nos. 371 and 372, Miller collection), and ten 

 from McCoy (Nos. 75834-75842 and 75844, U. S. National Museum, Bio 

 logical Survey collection), the latter kindly placed at my disposal by Dr. 

 C. Hart Merriam. 



H BIOL. Soc. WASH., Von. XI, 1897 (67) 



