Myodes lemmus, its Habits and Migrations in Norway. 
By 
R. Collett. 
(Read at the Meeting of the Society, March 22nd, 1895.) 
Or all European land mammals, M. lemmus is probably the 
only one which, at present, may be said to have its principal home 
in Norway. 
The genus numbers, as is known, but three species. Its 
nearest relative, M. obensis, Brants 1827, which only differs 
from M. lemmus, by a trifling variation in colour), does not 
appear further eastward than the White Sea, but is, however, 
distributed throughout Siberia, and Arctic North America to 
about the mouth of the Mackenzie river”. 
Considerably more divergent in appearance and habits is M. 
schisticolor, Lilljeb. 1844, which, unlike the others, inhabits the re- 
i Viz., the want of the black patch on the upper part of the head, 
and the foremost portion of the back. 
? Doubts have been expressed as to whether M. obensis is, in reality, 
entirely different from M. lemmus. Nordquist has shown (Vega- 
Expeditionens Vetensk. Resultater, B. 2, p. 79, Stockh. 1888), that 
several of the specimens obtained at Koljutschin Island (near Be- 
ring Straits), during the Vega Expedition in 1879, exhibited a transi- 
tion to M. lemmus, the foremost portion of their backs being more 
or less browny black, almost similar to the chief species. In their 
winter coat but a dark central stripe remains on that part. These 
specimens were obtained during the summer (June 2?st). M. 
obensis undoubtedly, however, occurs as a rule, as å well defined 
species. 
Chr. Vid.-Selsk. Forh. 1895. No. 3. je 
på 
