Synopsis of the Voles of the Genus Phenacomys. 83 



General characters. Most like P. orophilus, but color much more ochra- 

 ceous and ascending branches of premaxillse more expanded terminally. 



Color. Dorsal surface clay color suffused with ochraceous, the back 

 thickly sprinkled with black-tipped hairs ; feet dirty white ; belly yellow 

 ish white, the plumbeous under fur showing through irregularly; tail in 

 distinctly bicolor, brownish above, whitish below. 



Skull The skull is similar to that of P. orophilus, but the interorbital 

 ridges are slightly more developed (though not enough to form a median 

 sulcus), the terminal portion of the ascending branch of the premaxilla 

 is broader and the jugal is scarcely mortised into the zygomatic arm of 

 the maxillary. 



Teeth. Not appreciably different from those of P. orophilus. 



Specimens examined. One, the type. 



General remarks. Phenacomys preblei is closely related to P. orophilus, 

 from which it differs in yellower color and some slight cranial characters. 

 In one of the latter it approaches P. intermedias. 



Phenacomys latimanus Merriam. 



Phenacomys latimanus Merriam, North American Fauna No. 2, p. 34, 

 October 30, 1889. 



Type locality. Fort Chimo, Ungava, Labrador. 



Geographic distribution. Arctic and Hudsonian zones from northwest 

 ern Labrador to the north shore of Lake Superior. Limits of range not 

 known. 



General characters. Size small ; skull never developing sharply denned 

 interorbital ridges, even in extreme old age ; muzzle and face conspicu 

 ously yellower than rest of head. 



Color. Dorsal surface pale yellowish cinnamon-brown, clearer and 

 more tinged with reddish on muzzle and face ; region from eyes to base 

 of tail strongly shaded with blackish hairs ; feet and whole ventral sur 

 face whitish gray, the throat and belly somewhat darkened by the 

 plumbeous bases of the hairs; no distinct line of demarkation on sides, 

 but color of belly shading abruptly into that of back ; tail sharply bicolor, 

 dark brown above, whitish below; ears concolor with surrounding parts, 

 but region immediately behind ear generally paler. 



Skull. The skulls of adult specimens vary in basal length from 20 to 22 

 mm., and in zygomatic breadth from 13 to 14 mm. ; rostrum moderate 

 (nasals contained about three and one-half times in occipi to-nasal length) 

 rather more lightly built than in P. ungava, and with profile usually more 

 deflected from dorsal outline of frontals ; interorbital region faintly con 

 cave, never distinctly sulcate. 



Teeth. The enamel pattern of this species calls for no special remark. 

 The anterior loop of the front lower molar is usually cut on the inner side 

 by a deep reentrant angle, which is so much deeper than that on the 

 outer side as to destroy the bilateral symmetry of the loop. This char 

 acter occurs in other species, notably P. oropli'dus, but it appears to be 

 more constant in P. latimanus than any other. 



