Synopsh of the Voles of the Genus Phenacomys. 70 



Genus PHENACOMYS Meniam. 



Phenacoinys Merriam, North American Fauna, No. 2, p. 28, October 30, 

 1889. 



Type species.— PIic)u(co)nys uiteruiedius oNIerriain. 



Geogrnphk distribution. — Boreal North America from Atlantic to Pacific, 

 soutli to the Gulf of Saint Lawrence, the north shore of Lake Superior, 

 the coast of Oregon, and in the Rocky Mountains to Colorado. 



Generic characters. — Skull and teeth in general as in Microtna, but molars 

 distinctly two-rooted in the adult, and root of lower incisor never reach- 

 ing level of dental foramen. Reentrant angles on inner side of lower 

 molars very much deeper than those of outer side, not approximately 

 equal to outer angles as in .Uicrolns and Erotomys. 



Remarks. — Phenaconiys combines the palate, heavily built angular skull, 

 and strong sharply angled teeth of Microtias with the rooted molars and 

 short lower incisors of Erotomys. It differs from both Microtns and 

 Evotomys in the i-elatively great depth of the inner reentrant angles of 

 the mandibular molars. 



Key to thk Species of Phunacomys. 



Tail about 40 percent of total length . .lo)iijicaii<Iiis. 



Tail about 25 percent of total length. 



Face and muzzle reddish or yellowish in strong contrast 

 with rest of head. 



Skull of adult with deep frontal sulcus ungava. 



Skull of adult without frontal sulcus latimanus. 



Face and muzzle essentially same color as rest of head. 



Ascending branches of premaxilke broad intermedins. 



Ascending branches of premaxillae narrow. 



Color decidedly ochraceous preblei. 



Color gray orophilus. 



Phenacomys intermedius Merriam. 



Phoiacomys iiUermedins Merriam, North American Fauna, No. 2, p. 32, 

 October 30, 1889. 



Type locality. — Basaltic plateau about 20 miles NNW. of Kamloops, 

 British Columbia. Altitude 5,500 feet. Type No. 780, Mus. Geol. and 

 Nat Hist. Surv. Canada. Collected by Dr. Geo. M. Dawson. 



Geographic distribution. — Phenacomys iidertnediiis is known from the type 

 locality only. 



General characters.— "t^'v/.Q small; general color pale; feet light brown; 

 skull with interorbital region and ascending branches of premaxilla? very 

 broad ; front lower molar with five well developed salient angles on outer 

 side. 



Color. — Back grizzled grayish brown with a yellowish tinge, everywhere 

 sprinkled with black-tipped hairs which are most numerous on middle of 



