LEMMUS. 



Fig. 47. Lemmus trimucronatus. 

 No. 340 Field Columbian Museum Coll. Nat. size. 



Lower tooth row. 

 Enlarged 4 times. 



Upper tooth row. 

 Enlarged 4 times. 



Genl. Char. Smaller than Hudson Bay Lemming; head flat; 

 ears very short, hidden in fur; eyes small; upper lip deeply cleft, 

 inside of cheeks hairy. 



Color. Head and fore part of back mi.\ed clove brown and yel- 

 lowish brown, hairs tipped with blackish gray; lower back chestnut 

 brown; sides yellowish brown; belly bluish gray mixed with yellow- 

 ish brown hairs. Tail gray. 



Measurements. Total length, 120-127. 



a. — helvolvs. (Arvico/a), Rich., Faun. Bor. Amer., 1829, p. 128. 



T\pe locality. Alpine Swamps 56° North latitude (Drummond, 

 vide Rich). 



Geogr. Disir. Actic regions of North America. 



Getil. Char. Limbs short; nose short, blunt; head oval; eyes 

 small; ears broader than high, hairy; tail short, hairy; incisors pale 

 yellowish. 



Color. Above brownish yellow, or ruddy rust color mixed with 

 black; sides brighter yellow; under parts and limbs pale rust yellow 

 or tawny; margin of lips white; feet fuscous brown. Tail, above 

 dusky, beneath whitish. 



Measurements. Total length, 121; tail vertebrae, 7; hind foot, 32 

 (Fort Anderson). 



h. — yukonentis. (Lemmus), Merr., Proc. Wash. Acad. Scien., 1900, 

 p. 27. 

 Ty/>e locality. Charlie Creek, Yukon River, Alaska. 



