MICROTUS. 



Gfogr. Distr. Rocky Mountains and the plains from New Mex- 

 ico to British Columbia, and from the Black Hills, South Dakota, to 

 central Idaho, and the plains of the Columbia. 



Gfiil. Char. Equal in size to .)/. penmylvanicus: ears shorter 

 than fore foot; tail vertebr.x" scarcely longer than the head; middle 

 upper molar with five triangles; last upper molar has one anterior, 

 one interior and two exterior triangles, and a posterior bent crescent 

 occupying nearly half the tooth. With the loop of this crescent there 

 are five interior salient angles and three exterior. Anterior lower 

 molar has five interior salient angles and the loop, and four exterior. 



Color. Above, black hairs with yellowish brown tips, giving a 

 fulvous tinge. Beneath, dark plumbeous tinged with hoary. Tail 

 above dark brown; below hoary plumbeous. Feet dark brown. 



Mt-asurtHieiits. Total length, 93: tail vertebra', 23; hind foot, iS. 



(1. fonti^piiiif. {Afuro/ns), Bangs, Biol. Sec. Wash., 1896, p. 48. 



Type locality. Lake Edward, Quebec. 



Geogr. Distr. Quebec, Canada, west to Peninsula Harbor and 

 Nepigon, north shore of Lake Superior. 



Genl. Char. Size small, color dark, no rufous shades: rostrum 

 slender, bullae large. 



Color. Above sepia brown mixetl with black; beneath olive or 

 smoky gray; tail black above, gray beneath. 



Measurements. Total length, 151 ; tail vertebra', 41.5 ; hind 

 foot. 21. 



e.—liihrndnriu!'. {Microtiis), Bailey, Proc. Biol. Soc, Wash., 1898, 

 p. 88. 



Tvpe localitv. Fort Chimo, Ungava, Labrador. 



Geogr. Distr. Ungava, Labrador. Only known from the type 

 locality. 



Genl. Char. Skull flat ; postorbital ridge prominent ; nasals 

 short, cuneate: first upper molar usually with a posterior lobe on 

 eitlier side; audital bulla; small. 



Color. "Above dark brownish; belly whitish; tail bicolor; feet 

 pale." 



.\fidsiirements. Total length, 139; tail vertebra', 39; hintl 

 foot, 20. 



257. drummondi. (Arvnola). And. A: Bach., N. Am. Quad, iir, 



1854, p. 166. 

 microcephaliis, Khoads, Proc. .\cad. Nat. Scien. Phila., 1894, 



p. 286. 

 stonei, Allen, Bull. Am. Mus. Nat. Hist., 1899, p. 5. 

 Type locality. Near Jasper House, Rocky Mountains. Alberta. 



