244 GROUND FEET. 



arc nearly equi-distant, and all their points are 

 directed toward the same centre, so that in whichever 

 direction the prey writhes, it always runs itself more 

 and more upon the point of a portion of the claws, 

 and the trenchant edges at the same time tear and 

 mangle its flesh. The same position of the toes 

 enables the birds to perch on the points of rocks and 

 other places of observation, from t which they can dis- 

 cover their prey. But such feet are not well adapted 

 for walking ; and when the birds have to change their 

 place even for a short distance upon the ground, they 

 always raise or move the wings. Thus, though the foot 

 of birds of prey is used for various purposes upon the 

 ground, it cannot be regarded as a foot well adapted 

 for any kind of progressive motion. The feet of 

 ravens, and several other omnivorous birds, partake 

 a little of this character, and hence they hop rather 

 than walk, and partially raise the wings to balance 

 themselves. 



GROUND I I I I. 



Birds have so many and so different species of 

 action upon the ground, and the ground itself offers 

 so many different kinds of surface, that it is not very 

 easy to reduce the feet to any thing like an explicit 

 system. If the bird is a swift runner, the tarsi are 

 long, the thigh bones articulated a little farther for- 

 ward, and their action more free ; but then the termi- 

 nation of the foot, which is usually attended to in the 

 descriptions of the feet of birds, varies with the 

 ground on which it is to be used, and this again 

 causes a modification of the other parts of the leg. 

 If the back toe is long, and articulated at the same 

 leyel with the other toes, then the foot must be 



