302 



GENERAL ORNITHOLOGY 



organ at all, the trachea forking as simply as possible. Others, as 

 the common fowl, have a fair syrinx, but no muscles ■whatever to 

 modulate their j^astoral lays. Others have one, two, or three pairs 

 of intrinsic muscles ; to which may or may not be added a sterno- 

 tracheal with syringeal attachment. It is not so much the bulk or 

 mere fleshiness of the syrinx that indicates musical ability ; but the 

 distinctness of the several muscles, and the mode of their insertion. 



Fig. 99. — Coiling of the windpipe in tlie sternum of Grws americana ; reduced. 



which result in endless combinations of rotating and rocking move- 

 ments of the parts, whereby an infinite modulation of the musical 

 tones becomes possible. In Oscines there are normally five or six 

 pairs of muscles, without counting the extrinsic sternotracheales ; 

 and the gist of the arrangement, in these melodious Passeres, is the 

 attachment of the muscles to the ends of the upper bronchial half- 

 rings, as far as the third one. As Professor Owen remarks with 

 appreciative feeling, " the manifold ways in which the several parts 

 of the complex vocal organ in Cantores may be affected, each of the 



