V* 



THE STRUCTURE OF 

 THE FOWL 



I 



INTRODUCTORY 



The zoological position of the class Aves, to 

 which the fowl belongs, may be indicated 

 briefly as follows : — 



I. Invertebrates ; animals without a back- 

 bone. 

 II. Vertebrates ; animals possessed of a back- 

 bone or vertebral column. 



(1) Cyclostomata, with no true jaws, 



e.g. the hag-fish and the lamprey. 



(2) Fishes. 



(3) Amphibians. 



(4) Reptiles. 



(5) Birds. 



(6) Mammals. 



It is generally admitted that birds may be 

 divided in the first place into two major groups. 



