348 ON THE LEGS AND FEET OF BIRDS. 



In the bird, the thigh is very short ; and the knee, which has no knee- 

 pan * in diving birds and some other genera, bends so high up that 

 it is in most cases concealed by the feathers. The most conspicuous 

 bone, which I have termed the shank-bone, has been variously consi- 

 dered by naturalists, according to the views which they have entertained 

 respecting its analogy with the bones of other animals. The Emperor 

 Frederick II. and Belon seem to have been among the first to compare 

 the shank-bone with the heel; Borelli terms it a foot-leg f ; Merrem, 

 Herrmann, Wiedemann, and Daudin, take it to be the heel ; Vicq d' 

 Azyr and Blumenbach consider it only a foot -bone ; while Stenson, 

 Cuvier, Tiedemann, Ranzani, Savi, Carus, and Meckel, think it is 

 partly a heel, and partly a foot-bone J. The arguments for the last 

 opinion are derived from refined and fanciful analogies of what is 

 termed representation, upon which it is not important to decide. 

 Though the thigh, however, is often called the leg, the word leg is at 

 table generally applied in the way adopted by M. Le Vaillant and 

 other naturalists. 



The lower extremity of the shank-bone has a projection correspond- 

 ing with each toe, and forming a sort of pulley to act as a moveable 

 joint. There are, consequently, three such pulley-like projections in 

 most birds ; but only two in the ostrich, which has not more than two 

 toes. In all birds that have four toes, with the exception of the swift, 

 the back toe has but one bone ; this back toe acting, as Willughby 

 observes, in place of a thumb. Birds have their toes for the most part, 

 proportionally much longer than other animals, while they are brought 

 more under the general centre of gravity by the bending of the thigh 

 upon the leg. 



The muscles which bend the parts of the leg and foot, are consider- 

 ably different in birds from other animals, and consist of three masses. 

 The first is in two portions, of which one arises from the outer knob 

 of the thigh bone, and the other from its hinder surface, running down 

 to be inserted in the toes. This is connected, by fibres, with another 

 muscle, which arises from the inner side of the thigh, runs over the 

 knee down to the toes, where it is inserted so as to bend them when the 

 thigh and the heel are bent. 



* In Latin, Rotula. 

 f In Latin, Crus-pcdale. 

 In Latin, Os tarso-metastarso. 

 Technically, Condyle. 



