VERTEBRATA. 



333 



FIG. 315 Prairie-chickeij (Cupidonia cupido). 



Western prairies. 



being united by a short web, and terminating in blunt 



claws. The legs are usually feathered to the heel, some- 

 times (as in Grouse) 



to the toes. The 



feathers of the body 



are large and coarse. 



The males generally 



have gay plumage, 



and some appendage 



to the head. The 



nostrils are covered 



by a scale or valve. 



Their main food is 



grain. Such are the 



Grouse, Partridges, Turkeys, Pheasants, Poultry, and Cu- 



rassows. 



C. AERIAL BIRDS. This highest and largest group in- 

 cludes all those Birds whose 

 toes are fitted for grasping 

 or perching, the hind toe 

 being on a level with the 

 rest. The knee is free from 

 the body, and the leg is 

 generally feathered to the 

 heel. The wings are adapt- 

 ed for rapid or long flight ; 

 and they hop, rather than 

 walk, on the ground. 170 

 They always live in pairs; 

 and the young are hatched 

 helpless. 



7. ColwnbcE, or Pigeons 



and Doves, stand intermediate between the terrestrial and 



perching Birds, as the Flamingoes, and link the aquatic 



and terrestrial. They differ from the typical Rasores in 



FIG. 316. Ring-dove 



England. 



