194 MICROTIN^ 



1795. Lemmus lemmus Link, Zool. Beytr., 1, pt. 2, p. 75. 

 1811. Myodes lemmus Pallas, Zoogr. Rosso-Asiat., 1, p. 172. 



1820. Lemmus borealis Nilsson, Skand. Faun., 1, p. 185 (substitute 

 for lemmus). 



1821. Marmotta lemmus Blumenbach, Handb. Naturgesch., 10'° 

 Aufl., p. 86. 



1822. Lemmus norvegicus Desmarest, Mamm., 2, p. 287. 

 1827. Hipudceus norvegicus Lesson, Man. Mamm., p. 277. 



1829. HypudcBUS norvegicus Fischer, Syn. Mamm., p. 297 (misquoting 



Lesson). 

 1848. Myodes lemurus Gray, P.Z.S., 1848, p. 43, Sweden [misprint 



for lemmus]. 



Type. — Unknown. 



Type locality. — Mountains of Lappmark, Sweden. 



Range. — From sea-level upwards in northern Scandinavia and 

 Finland, eastwards to the western coast of the White Sea. In 

 normal years extending southwards upon the mountains, in the 

 Birch Zone and at higher levels, to the neighbourhood of 

 Christiansand in Norway, and to northern Wermland in Sweden. 

 In " Lemming years " the species descends to sea-level, over- 

 running the coastal districts even in the extreme south of 

 Norway. 



Characters. — Essential external, cranial and dental characters 

 as described under the genus; hind-foot 17 to 20 mm., condylo- 

 basal length 27-6 to 33. 



Colour brilliant ; pied black and yellow above, yellow below. 

 Hairs everywhere with dark bases, except on lips and chin where 

 they are hght throughout. Fore-part of upper surface, including 

 the top of head and withers, black; the black area sharply defined 

 laterally, its boundary running backwards from the tip of the 

 muzzle along the lower borders of the eyes to the ears ; thence 

 curving upwards to the spine behind the shoulders, whence it 

 is continued along the spine to the middle of the back or to the 

 rump as a more or less well-defined narrow dorsal stripe. This 

 black area is interrupted on each side by a conspicuous biiffy 

 p^tch which lies above the ear and is connected with the posterior 

 canthus of the eye by a narrow buffy streak, and sometimes 

 with the ochraceous colour of the ventral surface by a post- 

 auricular ventral extension ; sometimes these patches are con- 

 tinuous with each other across the nape, but usually they are 

 separated by a black stripe which connects the solid black areas 

 on the top of the head and over the shoulders. On the posterior 

 half of the back a more or less sharply defined blackish streak 

 runs backwards along the upper flank on each side and inwards 

 over the hip to meet its fellow in a rather sharp V on the rump. 

 Remainder of the body ochraceous or tawny; darker, mixed 

 with dusky hair-tips, over the loins ; clearer and paler on the 

 ventral surface, lightening to pale buff or whitish on throat, 

 chin, and upper lips. Hands and feet light buff with a more 

 or less evident silvery gloss. Tail pale buff, with a more or 



