28 Kitchen on the Inferior Larynx in Birds. [January 



vocal purposes, at first view seems very much like certain musi- 

 cal wind instruments. The true rima glottidis at the upper 

 part of the windpipe simulating the outlet of the instrument, 

 while the bronchial larynx is furnished with a peculiar tense 

 membrane that looks as if it might perform the same duty as the 

 reed in a clarionet. This is probably true in a certain degree, 

 but no instrument has ever yet been able to imitate the best of 

 bird-song. 



The superior larynx is noted for its simplicity of construc- 

 tion and moderate functional action, in comparison with the 

 larynx of man. As one examines it, the rigidity of the organ is 

 conspicuous. Several of the upper tracheal rings are fused 

 together and represent the human cricoid cartilage. Resting on 

 this, forming the anterior part of the rim of the structure, is an 

 oval or triangular thyroid cartilage. But at the rear of the organ, 

 in place of the two pyramidal arytenoids, as in man, we find a 

 large broad sesamoid plate running across the posterior wall, and 

 on either side are two small cartilages connecting this plate with 

 the thyroid, thus completing the circle of the laryngeal frame- 

 work. The two arytenoids rest on top of this framework on 

 either side, running well forward, and their inner margins 

 form the rima glottidis, and this rim is the only substitute for 

 the vocal cords of man. As we look inside of the organ we find 

 no trace of those ligaments. The muscles of this structure are 

 two. A surrounding sphincter muscle which closes the rim of 

 the organ more or less tightly ; and a pair of thyreo-arytenoidei 

 which open the laryngeal fissure by drawing apart its rims. 

 This fissure, in opening, is drawn furthest apart anteriorly, while 

 in the human larynx the attachment of the vocal ligaments are 

 close together in front, and they open widely at the back of 

 the organ when the glottis is dilated during inspiration. 

 Although this simple larynx has small functional ability, it is 

 the point at which the true voice of birds is formed ; especially 

 the voice that is analogous to that of man ; the voice that is 

 peculiar to all the Clamatores. The Oscines are really not 

 singers in the fullest sense of that word. Besides being able to 

 break up the outgoing current of air into the vibrations which pro- 

 duce the rather coarse, harsh, and monotonous voice of the 

 Clamatores, the rim of the glottis, in certain degrees of approxi- 

 mation, can produce the 'hiss' and a sort of 'whistle' similar to the 



