340 HUMBOLDT ON THE OHGANS OF THE VOICE. 



and the Ardea johannce. This handsome bird is four feet four 

 inches high, when he stands with his neck elongated, and his 

 greenish bill raised. The two anterior bonelets, or the branches of the 

 anterior compass (if I may be allowed the expression,) are immoveable, 

 while the posterior compass, which is placed over and embraces the 

 other, extends its branches by means of two fleshy muscles which are 

 placed outside the bony glottis. These posterior bonelets might be 

 likened to the arytenoid cartilages, while the anterior by their position 

 might correspond with the thyroid cartilage of mammiferae ; but, in 

 classes of animals whose entire organisation is so different, these com- 

 parisons, most frequently, only serve to lead to very inaccurate ideas. 



It follows from this construction of the superior larynx, that the 

 rima or opening of the glottis, confined by the anterior bonelets, can 

 scarcely ever become either widened or more contracted ; and that it is 

 by the action of the posterior branches, which are placed at the outer 

 border of the glottis, that the internal capacity of this organ becomes 

 changed. The voice is always projected through the same opening, 

 but the rapidity with which this is effected, depends as much upon 

 the impulse it has received in the inferior larynx, as upon the approxi- 

 mation of the bonelets of the glottis. 



But the modification of the sounds does not depend solely upon the 

 extremity of the trachea, nor upon the form of the two larynxes. The 

 whole trachea in some of the tropical birds, presents very extraordinary 

 appearances. In the same species, the trachea in the male is sometimes 

 twice the length of that in the female : Linnaeus has already announced 

 this in the description of the Phasianus parraka. We also meet with 

 this difference in several swimming and wading birds of Europe, in 

 storks, cranes, and herons ; and M. Daubenton has observed it in the 

 fine genus Crax, the Koco of the tropics, which has often served us for 

 food in the woods. There is an extraordinary prolongation and sinuosity 

 of the trachea in a new species of pheasant, which I shall describe under 

 the name of Phasianus garrulus. This pheasant, which must not be 

 confounded with the Phasianus motmot, is very common north of the 

 equator, in the river Magdalena, in the province of Caracas, and in New 

 Andalusia. Flocks of from sixty to eighty perch themselves upon the 

 dead branches of contiguous trees, and fill the air with their piercing 

 cries of catacras ! catacras ! 



I found the length of the trachea in the male of this species, to be, 

 from the superior larynx to the bronchi, fifteen inches seven lines, 

 while the female's was but five inches four lines. That in the male 

 first descends among the teguments under the sternum as far as the 



