The Framework of the Bird 



9' 



the adult bird the shifting l)ackwar(l of this bono until it 

 is parallel with the ischium is wholly an avian feature. 



Fig. GG.— Bullfrog. The bend in the back shows the great development of the 

 ilium tor bipedal locomotion in the sense of leaping ability. 



Wings 



We will now consider the framework of the fore limb, 

 or wing, of a bird, and a glance at the illustration show- 

 ing the arm of a man and the wing of a bird will at once 

 make plain the relation between the two. Here we again 

 find a great help in the fact that many of the bones keep 

 to their respective places in frogs, lizards, birds, and man./ 



We know but little of the direct change from a fin to 

 a hand or foot, although there are some fishes living -it 

 the present day with large hnger-like bones in their pec- 



