354 



The Bird 



of years, or thereabouts, since the days of its venerable 

 prototype. 



This is the kind of generalized organ which, we should 

 think, would be able to cope with changes in the bird's 

 surroundings more successfully than any other; but that 

 this theory fails when put to the test is proved by the 

 variety of specialized toes and legs which we may observe 



FIG. 283. Foot of Alligator. 



among the birds on the earth to-day. Indeed, in the 

 variety of uses which they subserve, the feet and legs 

 of birds are second only to the bills. 



A classification of birds, generally accepted for many 

 years, was based on the uses of the feet, or mode of loco- 

 motion. In this scheme birds were divided into runners, 

 scratchers, climbers, swimmers, perchers, etc. Although 



