THE 



STRUCTURE AND CLASSIFICATION 



BIltDS 



THE GENERAL STRUCTURE OF BIRDS 



As the aim of the present work is to detail the characteristics 

 of the various groups of birds, I do not propose in this 

 section to do more than give a general account of bird 

 anatomy. A fuller description will be found in the part 

 relating to birds by Dr. Gadow, in Bronn's ' Klassen und 

 Ordnungen des Thierreichs,' where much that will be found 

 here in the accounts of the several families of birds is 

 treated of in the introductory chapters. The greater part of 

 this I dehberately omit, to save repetition. 



The Foot 



The feet of birds show a large amount of variation, 

 which is not for the most part of great value in the deter- 

 mination of affinities. That the older naturalists paid great 

 attention to these facts is evident from the names Palmipedes, 

 Cursores, &c. No. bird has, save for abnormalities, such as 

 the Dorking fowl, more than four toes. The opposite ex- 

 treme is reached by the ostrich, which has only two. That 

 the three-toed and, a fortiori, the two-toed condition has 

 been arrived at by a reduction from four toes seems to be 

 shown by the condition of the feet in certain petrels, where, 



B 



