23O VERTEBRATES : BIRDS. 



extraordinary protuberance, which in some cases is as 

 large as the bill itself. By their bill these birds are allied 

 to the Toucans, but their general carriage and habits ap- 

 proximate them to the Crows. 



SUB-SECTION IV. 



THE ORDER OF RASORES, OR SCRATCHERS. 



THE Order of Rasores comprises Birds which have the 

 bill not longer than the head, the terminal portion 

 more or less vaulted, and hard, and with or without a 

 soft skin intervening between it and the head, and the 

 nostril with a fleshy scale extending over its upper edge. 

 With few exceptions, they have a heavy body, short wings, 

 rather stout legs, and large tail. They live mainly upon 

 the ground, are social in their habits, and feed princi- 

 pally upon nuts, berries, buds, tender leaves, and grain. 



The Rasores comprise two Sub-Orders, Columbas 

 and Gallinae. 



The Sub-Order of Columbae or Doves comprises those 

 which have the bill shorter than the head, the basal por- 

 tion covered by a soft skin in which the nostrils are sit- 

 uated, the hind toe on the same level as the others, and 

 the anterior toe without a basal membrane. They live in 

 pairs, lay generally but two eggs for a brood, but breed 

 often, and feed their young, which are hatched in a very 

 feeble condition, with macerated food from their own 

 crops. Bonaparte calls the true Doves or Pigeons Gy- 

 rantes, and divides them into four families ; Treronidae, 

 of the Old World, and especially of the islands of the 

 Pacific, which have the bill robust and tumid, the feathers 

 soft and without lustre, the prevailing color green, and 

 the tail with fourteen feathers ; Columbidae, universally 

 distributed ; Caloenidae, of the East India islands ; and 

 Gouridae, of New Guinea. 



