KEY TO LAND MAMMALS OF NORTHEASTERN NORTH AMERICA IO5 



Microtus chrotorrhinus ravus Bangs Labrador rock vole 



1898Microtus chrotorrhiuus ravus Bangs, Proc. biolog. soc. 



Washington. 16 Nov. 1898. .12 : 188. (Black bay, Labrador) 

 1900 Microtus chrotorrhinus ravus Bailey, North American fau- 

 na. June 1900. No. 17, p. 59. 

 General color of upper parts light umber brown ; muzzle patches pale tawny 

 ochraceous spreading over ivhole face. Total length, 160 (6i) ; tail vertebrae, 45 

 (If) ; hind foot, 22 (f). (ravus; Lat., yellow gray) 



The Labrador rock vole is thus far known from Black bay, Labrador 



only. ^ ' 



Microtus breweri (Baird) Miiskeget island vole ^ 



1857 Arvicola breweri Baird, Mamm. N. Am. p. 525. (Muskeget island, 



Massachusetts) 

 1896 Microtus breweri Miller, Proc. Boston soc. nat. hist. June 1896. 



27 : 75. 

 1900 Microtus breweri Bailey, North American fauna. 6 June 1900. 



no. 17, p. 26. 

 Light gray, pure and whitish on belly, dull, tinged with wood brown and 

 sprinkled with blackish liairs on back ; fur harsh and coarse. Total length, 195 

 (7f) ; tail vertebrae, 48 ( H ) ; hind foot, 24 (if), (b re weri; name from that 

 of Thomas Mayo Brewer) 



The Muskeget island vole is peculiar to the island of Muskeget, off 

 Nantucket, Massachusetts. 



Microtus enixus Bangs Hamiltoii mlet vole 



1896 Microtus enixus Bangs, American naturalist. Dec. 1896. 30 : 1051. 



(Hamilton inlet Labrador) 

 1900 Microtus enixus Bailey, North American fauna. 6 June 1900. no. 

 17, p. 24. 

 Upper parts dark nmber brown, much sprinkled with black hairs ; under parts 

 dark gray occasionally slightly washed with buffy, teeth very lightly huilt, the 

 front teeth slender and strongly projecting, the row of cheek teeth averaging less than 

 i basal length of skull. Total length, 190 (7^) ; tail vertebrae, 60 (21) ; hind 

 foot, 22 (I), (enixus; Lat., zealous) 



The Hamilton inlet vole is abundant throughout northern Labrador. 

 Microtus pennsylvanicus (Ord) Field mouse 



Upper parts dark brown, much sprinkled with black ; under parts gray, usually 

 washed with buffy; teeth strong, the front teeth heavy, not directed noticeably forivard, 

 the roiv of cheek teeth averaging more than i basal length of skull; skull with long, 

 narroiv braincase. (pennsylvanicus: N. Lat., Pennsylvauian) 



This is the common field mouse abundant and well known throughout 

 eastern North America from Labrador to North Carolina, and ranging 



