14 WINGS OF BIRDS. 



constructed, is converted into an instrument of flight, by having appended to its 

 posterior edge a large lamina or plate, composed of a series of strong, elastic fea- 

 thers, named quills, and varying in firmness, form, length, and relative propor- 

 tion, according to the kind of flight necessary for the species. When about to be 

 employed, the parts which in a state of rest were folded up, are stretched out so 

 as to unfold the feathers somewhat in the manner of a fan, and form a horizont- 

 ally expanded lamina, which, being alternately raised and forcibly pulled down, 

 furnishes a lever, whereby the body is elevated into the air ; when, with repeated 

 strokes, by which the wing is alternately drawn upwards, forwards, and inwards, 

 and then more forcibly outwards, downwards, and backwards, the bird advances, 

 directing its course by the tail, but more especially by a difference in the action 

 of the two wings. 



The wood-cuts represent the wing of a Domestic Pigeon, Columba livia, de- 

 prived of all its feathers, excepting the quills, and viewed, first from above, Fig. 

 1 ; then from beneath, Fig. 2. In these figures, a is a portion of the body ; b, c, 

 the humerus or brachium ; c, d, the cubitus or antibrachium ; d, f y the hand, 

 composed of d, e, the carpus and metacarpus ; y, the pollex or outer finger, and 

 e,f, the other fingers. The ten quills attached to the hand, from d toy", are the 

 primary quills ; those attached to the cubitus, from c to d, are the secondary 

 quills. They are arranged, as is observed, in two distinct sets. Those on the 

 first finger, g t are named alular quills. Besides these, there are large feathers, 

 not, however, so strong, attached to the skin along the edge of the humerus, b, c ; 

 but these, which are named tertiary quills, have been removed . Now, the order of 

 nomenclature, if numerical, ought to have commenced at the part nearest the body: 

 those on the first point or brachium, ought obviously to have been named primary ; 

 those on the second, secondary ; and those on the third, tertiary. A decidedly 

 preferable mode, however, is to name the quills according to their relations : — 

 brachial, cubital, and digital ; those on the first finger alular. Besides the fea- 

 thers, there is represented the muscular apparatus of the wings, as seen after the 

 skin has been removed. The muscles to be described are; — 1st. Those inserted 

 into the scapula; 2ndly, Those inserted in the brachial bone; 3rdly, those 

 inserted into the bones of the hand. In the figures the same muscles bear the 

 same numbers. 



1. Mnscles inserted into the Scapula. 



1. The first muscle is the trapezius, which, arising from the spines of the last 

 cervical, and all the dorsal vertebrae, excepting the last two, is inserted into the 

 dorsal edge of the scapula, and the extremity of the furcula. Its action is to 

 draw the scapula towards the spine, and to fix it during flight. 



Under this are the rkornboideus, which passes from the spines of some of the 

 anterior dorsal vertebrae, to the dorsal edge of the scapula ; and the levator sea- 



