Vol. XI, pp. 73-75 ' April 21, 1897 



PROCEEDINGS 



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 ChihtKS 

 has been recognized — the 'Arvicola orcyonl^ of Bachnian, which 

 inhabits tiie coast region of Oregon. 



Wliile 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 nienil^er of the group. 

 It is apparently an alpine species and difi'ers strikingly from 

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

 form, also having a short tail, but mucli darker than either oregoni 

 or the Crater Lake species, Avas 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 sunmiarized 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 I'egion, where it ranges from tlie northwestern 

 corner of California (Crescent City) to southern British Colum- 

 bia (Port Mood}^ and Agassiz). The extreme northern and 

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

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

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

 mapping tlie distinctive ranges of oregoni and serpens. 



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



17— Biol. Sue. Wash., Vol. XI, 1897 (73) 



