KEY TO LAND MAMMALS OF NORTHEASTERN NORTH AMERICA lOI 



Genus Dicrostonyx Gloger 



1844 Dicrostonyx Gloger, Gemeimi. hand- u. hilfsljuoli d. naturgesch. 

 l:xxxi, 97. Type Mus hudsonius, Pallas. 

 Pace of each upper front tooth smooth, grinding teeth without roots (prongs), 

 ahull large, heavily angular ; ears reduced to mere naleed rims; claws very large; 

 in winter apparenthj doiMe ; tail very short with a long brush of stiff hairs; fur 

 turning white in winter. (Diorustonyx ; Gk., fork claw) 



The genus Dicrostonyx, containing the lemmings which turn 

 white in winter, is circumpolar in distribution. One or more forms occur 

 in northern Europe and Asia, The following species is found in Labra- 

 dor. 



Dicrostonyx hudsonius Pallas Labrador lemming 



1778 Mus hudsonius Pallas, Nov. spec, quadr. glir. ord. p. 203. 

 1897 Di ores ton yx hudsonius Bangs, Proc. biolog. soe. Washington. 

 11 : 237. 



lu summer ahout the color of a Maltese cat, slightly varied with rusty ; a 

 narrow black line down middle of back; in winter pure white. Total length, 

 150 (6); tail vertebrae, 21 (13); hind foot, 21(19). (hudsonius; N. Lat., 

 Hudsonian) 



The range of the Labrador lemming is imperfectly known. The 



animal occurs on the barrens of northern Labrador, south at least to 



Hamilton inlet. 



Genus Fiber Cuvier 



1800 Fiber Cuvier, Lemons d'anat. eomp. 1, tab. 1. (Described in Tab. 



elto.de I'hist. nat. des anim. 1798, p. 141) Type Castor zibethious 



Linnaeus. 



Front teeth without grooves, broader than deep; grinding teeth with roots 



(prongs), body short and thick ; tail long, flattened laterally. (Fiber; Lat., 



a beaver) 



The genus Fiber containing the well known muskrat, is peculiar to 

 America. Seven forms have been described, but their interrelationships 

 are very imperfectly understood. Two species occur within our limits. 



SPECIES OF FIBER 



Upper lip yellowish brown, total length over 500 (19f ) F. zibethicus 



Upper lip white, total length under 500 (191) F. obscurus 



Fiber zibethicus Linnaeus Muskrat 

 Size usually large; hind foot generally about 80 (3A) color very vari- 

 able; upper lip yellowish brown, (zibethicus; Lat., a civet, in allusion to 

 the musky odor) 



The muskrat occurs throughout North America south into the lower 

 austral zone. It is divisible into four or five races, two of which occur 

 within our limits. 



