THE ANIMAL KINGDOM. 301 



though they possess wings large enough, are never known 

 to quit the site they have chosen. Thus the Nycteris of 

 Upper Egypt, which can make itself exceedingly buoyant 

 by filling with air certain pouches under its skin, scarcely 

 quits the sombre windings of the pyramids and temples of 

 ancient Egypt, where it sometimes swarms in such numbers 

 as to extinguish, when flitting about, the torches carried by 

 the travellers. 



But some mammals, though placed in circumstances much 

 less favorable than other animals, nevertheless effect migra- 

 tions, the magnitude of which and the intelligence they 

 display awaken astonishment and admiration. 



Nothing presents a more imposing spectacle than the im- 

 mense troops of buffaloes which traverse the prairies of the 

 Far West in the Territories of the United States. When the 

 time appointed by the decree of Providence arrives, one of 

 these savage mammals constitutes himself chief of the emi- 

 grating troop. His roars resound, and he soon gathers round 

 him a formidable troop, ready to follow him across the wil- 

 derness. " When the moment arrives," says Chateaubriand, 

 " the leader, shaking his mane, which hangs from every part 

 over his eyes and curving horns, salutes the setting sun by 

 lowering his head and lifting up his back like a mountain ; 

 at the same time a dull sound, the signal of departure, issues 

 from his deep chest, and then all at once he plunges into 

 the foaming waves, followed by the multitude of heifers and 

 bulls which roar lovingly after him." 



The migrations of the squirrels, which fill with life the 

 forests of old Scandinavia, if less noisy, are marked by more 

 ingenuity. 



