eae The Bird 
a 
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 
Fic. 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 
