PHENACOMYS. 167 



Sub. Fam. IV. Microtinae. 



G. S. Miller, Genera and Subgenera of Voles and Lemmings. N. 

 Am. Faun., No. 12, 1896. 



Molars imperfectly rooted or rootless (e.xcept Phenacomys and 

 Evolovivs, which have rooted molars in old adults); swelling on inner 

 side of mandible caused by root of lower incisor, between condyle 

 and the descending process, the latter hamular; palate arched; nasals 

 not extending beyond premaxillaries. 



51. Phenacomys. 



G. S. Miller, Synopsis of the Voles of the Genus Phenacomys, Proc. 

 Biol. Soc. Wash., 1897, pp. 73-87. 



Phenacomys. Merr. N. Am. Faun., No. 2, 1889, p. 28. Type, 

 P. intermedins, Merr. 



Skull and teeth as in Microtus, but the adult has the molars two- 

 rooted, and the root of lower incisor does not reach the level of the 

 dental foramen. Lower molars on inner side have deeper reentrant 

 angles than on the outer. 



Fig 36. Phenacomys orophiius. 

 No. 5053 Field Columbian Museum Coll. Nat. size. 



Lower tooth row. 

 Enlarged 5 times. 



Upper tooth row. 

 Enlarged 5 times. 



232. intermedius. {Phenacomys), Merr. N. Am. Faun., No. 2, if 

 P- 32- 



Type locality. Kamloops, British Columbia. 



Geogr. Distr. Known only from type locality. 



