Distribution. The mountain trads of Southern Norway, 

 from Rennebo and Opdal in the North, to the Øjer Mountains 

 and Valders in the South (Lat. 63°— 61° 10'). Height above 

 the sea tevet 440—1030 meters. First discovered in 1907 ; so 

 far 20 specimens have been preserved. 



In the Summer of 1907 I received from a correspondent 

 in Opdal, on the northern slope of Dovrefjeld, a fresh specimen 

 of Sicista subtilis (Birch Mouse), caught on the 26 th of August 

 of the same year 1 ). 



The species must be considered as a remarkable and unex- 

 pected survival of an invasion of animals and plants amidst 

 the cold climatic conditions and peculiar natural surroundings 

 which characterised the period after the last great glacial period 

 in Europe and which is known by the name Steppe Period 2 ). 



In Western Europe the Birch Mouse is extinct throughout 

 a large area. In Sweden only one single example has been 

 found hitherto with certainty, (at Landscrona in July 1835), but 

 it is not improbable that it may still exist there on the fron tier 

 mountains adjoining the Trondhjem Stift, or further towards 

 the South. 



! ) The correspondent had received traps and instructions concerning the 

 capture of Microtes and other small raammals for the Christiania 

 Museum. 



2 ) An occurrence of this and other steppe rodents as early as in the 

 interglacial period has not been stated with certainty. 



