358 NATURAL ITISTORY READER. 



donkey does), he pounced upon his prey. But, instead ol 

 taking it directly into his mouth, he covered it with his 

 body and heat it by aid of its arms, etc., into the bag 

 formed by the interfemoral membrane. He then put his 

 head under his body, withdrew the fly from the bag, and 

 devoured it at leisure. 



11. " This appeared to be always the modus operandi, 

 more or less cleverly performed. Several times, when the 

 fly happened to be on the flat surface of the ground, the 

 capture appeared more difficult, and my little friend was, 

 by his exertions, thrown on his back. The tail could then 

 be seen turned round, with its tip and the margin of the 

 membrane pressed against the stomach, forming a capital 

 trap, holding the fly, the captor remaining on his back til] 

 he had withdrawn the fly from the bag." 



Professo* Bun G. Wtldet 



THE LEMMING AND ITS MIGRATIONS 



1. The Norway rat, of which we wish to say a few 

 words, is the lemming, a species of the mouse-tribe, some- 

 what smaller than the Guinea-pig, to which in form it 

 bears a considerable resemblance, only the head and body 

 are flatter. Its length is about six inches, of which the 

 short stump of a tail forms half an inch. It is black in 

 color, mottled with tawny spots, which vary in their dis- 

 position in different individuals, and the belly is white, 

 with a slight tinge of yellow. The fore legs are short and 

 strong, and the hind legs are nearly one half longer than 

 the former, enabling it to run with considerable speed. 

 The feet are armed with strong hooked claws, five in num- 

 ber, enabling it to burrow in the earth, and among the 

 frozen snows of its native region. 



