THE STRUCTURE OF 

 THE FOWL 



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. 



