VOL. XI, PP. 73-75 APRIL 21, 1897 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



THE VOLES OF THE SUBGENUS CHILOTUS, WITH 

 DESCRIPTIONS OF NEW SPECIES. 



BY C. HART MERRIAM. 



Heretofore only a single species of Baird's subgenus Chilotus 

 has been recognized the t Affricola oregoni' of Bachman, which 

 inhabits the coast region of Oregon. 



While making a Biological survey of the Crater Lake region, 

 in the southern part of the Cascade Range in Oregon, last August, 

 Mr. Vernon Bailey and I secured a new member of the group. 

 It is apparently an alpine species and differs strikingly from 

 M. oregoni in much paler coloration and shorter tail. A third 

 form, also having a short tail, but much darter than either oregoni 

 or the Crater Lake species, was obtained by Mr. Streator at 

 Agassiz, in British Columbia. The three forms constitute a very 

 compact group (subgenus Chilotus Baird), differing from all the 

 other Voles in a combination of characters which have been so 

 recently summarized by Mr. Gerrit S. Miller, Jr., in his admirable 

 paper on The Genera of Voles and Lemmings* that it is unneces 

 sary to repeat them here. The subgenus is restricted to the 

 northwest coast region, where it ranges from the northwestern 

 corner of California (Crescent City) to southern British Colum 

 bia (Port Moody and Agassiz). The extreme northern and 

 southern limits of its range have not been determined. M. bairdi 

 is clearly a mountain animal, confined to the Cascade Range, 

 but the data at present available are not sufficient to admit of 

 mapping the distinctive ranges of oregoni and serpens. 



* North Am. Fauna, No. 12, pp. 60-62, July, 1896. 

 17 BIOL. Soc. WASH., VOL. XI, 1897 (73) 



