1895.] MYODES LEMMUS. ES 
12. Examples of Migratory Years. 
In illustrating the route adopted by the hordes of lemmings 
in their advance during the great migratory years, I will enter 
more fully into a few of the migrations of late years, two of 
which have sent individuals right down to the city of Christiania. 
The migration of 1862—63 originated in the mountain cen- 
tres mentioned as No. 1 (p. 34), especially on the *Lang-Fjel- 
dene” and its branches, while on the other hand the more east- 
ern ranges of the mountains (such as those to the eastward of 
Gudbrandsdalen) mainly became involved in it the following year. 
Early in the summer of 1862, all the nests were filled with 
young, and, later on in the year, all the mountains in those di- 
stricts became alive with them, especially the Jotunheimen, the 
mountains of Valders, and the Hallingdal and Numedal moun- 
tains in the West, the Thelemarken mountains moreover, and all 
the Langfjeldene's southern branches in the South, besides the 
mountain ridges on the west coast which are connected to the 
central group. 
The migration commenced during the course of the summer, 
and simultaneously in all directions. It proceeded at no little 
speed. In October 1862, most of the valleys were filled with the 
swarms, and the first contingent had reached as far as the bor- 
ders of the lake Mjösen, and the eastern side of the Christiania 
Fjord down to the environs of Christiania, while to the West it 
extended to the head of the Fjords in Bergen Stift. Towards 
the South they reached in thousands all the towns from the 
Christiania Fjord to Stavanger. 
In the beginning of 1863, they were still assembled in great 
numbers on most of the above mentioned lowlands, but during 
the course of the summer of 1863, their decrease already began 
to be apparent in several districts of the interior!; åa few couples 
1 When in June and July that year I passed through Eker, Halling- 
dal, and Lærdal, there were but few living ones remaining there. 
