﻿EXTERNAL ANATOMY. 



WING FEATHERS. 



81 



wing. They consequently form three divisions, distin- 

 guished as the primaries, the secondaries, and the ter- 

 tials. The primaries are the outermost ; they are almost 

 always longest, and in swift flying birds, like the swal- 

 low, are double the length of any of the other quills. 

 The primaries are ten in number, and are attached to 

 the carpus, or those bones which represent the hand ; 

 they gradually diminish in length until they reach the 

 secondaries, which are inserted on the cubitus, or first 

 joint of the arm, and are usually only half the length 

 of the primaries. Lastly come the tertials, which have 

 their origin from the humerus. M. Cuvier has wrongly 

 applied the term scapular to these feathers, which are 

 unquestionably a portion of the quills ; neither do they 

 cover the scapulars, for their peculiar office is to fill up 

 the interval between the body and the wing, which 

 would otherwise arise when the latter was expanded, 

 and, by confining the air, to oppose a broader surface 

 of resistance to it. The true scapulars consist of a 

 longitudinal series of feathers very thickly crowded at 

 their insertion, commencing at the axillae, or armpit of 

 the wing, and intended to unite more perfectly the 



the wings of birds (that is, the quills) present. 



shoulder covers with the fea- 

 thers of the body. The sca- 

 pulars, therefore, are the 

 most convex feathers of the 

 bird ; they are also much 

 longer than those which they 

 join, and they gradually unite 

 with the tertials, which are 

 equally convex, and they serve, 

 when the wing is folded, to 

 protect the lesser quills. The 

 annexed figure {fig. 40.) 

 will explain all these parts at 

 once to the eye; and we may 

 now proceed to notice the 

 different modifications which 



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