384 Mr. Yarrell on the Trachea of Birds. 



cula at a right angle ; but becoming attached to this projec- 

 tion of the clavicle, receives from the point described its cen- 

 trical direction into the body. 'I'he whole length of the wind- 

 pipe in this bird is 4 feet 8 inches. 



Tab. XIV. is a representation of the trachea of the second 

 bird before referred to, and was also a male. It will be observed 

 to want part of the interesting character of the first specimen, 

 which the particular direction occupied by the leading portion 

 of the tube in this second renders unnecessary : but the enlarged 

 clavicle in this bird is on the right side, having a similar projec- 

 tion on its inner surface, forming a point of attachment for the 

 tube, and performing the same office as in the other instance. 

 It will remain for future investigation to show, whether in those 

 male birds possessing the extra convolutions of the trachea, the 

 enlarged clavicle is uniformly on the left side, and vice versa. 

 Four species of birds belonging to the Gallinaceous tribe have 

 been figured by Dr. Latham as possessing convolutions of the 

 trachea of various extent on the outside of the pectoral muscles : 

 the same parts have also been represented on a larger scale by 

 Mons. Temminck in his Histoire Natin-elle Gcncrale des Pigeons 

 et des Gallinacés, and are described as possessing voices exceed- 

 ingly hai'sh and loud. In this particular the Semipalmated Goose 

 agrees perfectly ; and in those species of Cranes and Swans 

 already referred to, the power and depth of tone will be found 

 to increase with the elongation of the tube. 



Of the true physiology of these variations in form and length- 

 ened convolutions little is known : that a connection exists be- 

 tween the sexual organs and those of the voice many proofs might, 

 be adduced ; and it is not the least singular property of these sin- 

 gularly formed windpipes, that the more complicated the struc- 

 ture of the tube, the more disagreeable is the sound of the voice, 

 the simple forms belonging to our most delightful song-birds. 



The 



