NATURAL HISTOUY. 



275 



O'er the wild waste the stupid ostrich strays 



In devious search to pick her scanty meal, 



Whose fierce digestion gnaws the temper'd steel." 



871. Why do fowls and other birds hustle themselves in 

 the dust? 



Because by this action they rid themselves of the vermin with 

 which they are liable to be troubled. 



872. On the same principle, swine wallow in the mire, and the rhinoceros and 

 the elephant roll their bodies in the mud to defend them from the breeze-fly. 



ORDER VI. CURSORES. 



873. Why is the order cursores so termed? 



Because the birds comprehended therein are distinguished by 

 possessing great powers of locomotion a-foot. 



874. The word cursores is 

 derived from the Latin verb 

 curro, "I run." These birds are 

 strictly and exclusively terres- 

 trial : have powerful and even 

 massive legs, moved by volumi- 

 nous muscles ; and wings which 

 are scarcely more than rudi- 

 mentary, barely enabling the 

 bird to rise above the surface 

 of the earth. The ostrich, dodo, 

 and cassowary are the chief 

 examples of this order. 



875. Why is the ostrich the swiftest, of animals ? 



Because of the very wide and scanty distribution of its food t 

 and the consequent large area over which it must travel in order 

 to obtain it. 



87G. Why does the 

 extraordinary power ? 



ostrich possess digestive organs of 



Because the scanty supply of food which the deserts 

 afford, renders it necessary that the bird should be able to 



