xxxvm 



INTRODUCTION 



/gfifiiti 



The wing itself is no less profoundly modified, as 

 we pointed out in an earlier part of this chapter. 

 Suffice it to say here, that of the original five fingers 

 but three "remain. Of these the thumb and third 

 finger are reduced, and little more than stumps ; while 

 the second finger has been elongated to form a long, 

 rigid rod, strengthened at the base by that portion of 

 the third finger which in ourselves contributes to form 

 the "palm" of the hand. In the bird's palm there 

 are but two bones, forming the base of the second and 

 third fingers respectively. 



The bird's wing folds in a peculiar manner, so as to 

 form a more or less Z-shaped rod, the humerus, or 

 ,CC. upper arm, form- 



ing the top of the 

 Z, the fore-arm the 

 %A,ft, downstroke, and 

 the hand the base 

 of the Z. 



When extended, 

 each of these divi- 

 sions or segments, 

 will be found to 

 support a series of 

 long, broad feath- 



FiG. 8— Wing of a bird, showing the ^^^' Those on the 

 FLIGHT FEATHERS AND SOME OF THE haud arc kuown as 

 COVERTS. -jjig primaries, and 



those on the fore-arm as the secondaries, while 

 those on the upper arm are sometimes described 

 as the tertiaries. These last form a double se- 

 ries, one attached to the upper and one to the under 



