56 BONES OF WINOS. 



short, the effective tail, as an organ of flight, being 

 composed of feathers ; but in all birds which have 

 much motion of the tail, the number of vertebrae in 

 that organ is considerable, though each individually 

 is very short, and the whole tapers to a point. 



THE WINGS. 



The wings, or anterior extremities of birds, which 

 correspond in position to the arms of man and the 

 fore legs in the mammalia, are adapted for flight only, 

 or, if they perform any other office, it is merely that 

 of balancing. Their general action in flight has 

 already been partially mentioned ; their several 

 parts, as they appear externally, will be mentioned 

 in the next section ; and their peculiar forms, as 

 adapted to the different habits of the various tribes 

 and genera, will be found in the accounts of these, 

 under their respective names. We shall here only 

 mention, therefore, that the bones of the moveable 

 part of the wing consist of a humerus, a fore-arm, 

 and a hand ; the part answering to the fingers of the 

 latter being very much elongated, with only one 

 finger fully developed, but the rudiments of the others 

 more or less apparent, according to the power of action 

 in the wing. The flying feathers are placed upon these 

 bones, and the thumb generally carries a little 

 plume of stiff but short feathers, which is called the 

 bastard wing, and in some species it is armed with 

 a claw or spine. The head of the hnmerus is arti- 

 culated nearly where the scapular bones, which are 

 embedded in the muscles on the shoulder, the cora- 

 coid bones which proceed from the anterior parts of 

 the sternum, and the furcal bone, or united clavicles, 

 which projects as an arch in front of the breast, 

 protecting the vessels of the throat, at the same time 



