THE VOICE. 



599 



is not essentially different from that of man. Growling is the 

 result of a functional activity of .the vocal mechanism, not un- 

 like that of man when singing a bass note; barking, of that 

 analogous to coughing or laughing, when the vocal bands are 

 rapidly approximated and separated. 



The grunting of hogs and the lowing and bawling of horned 

 cattle are probably very similar in production, so far as the 

 larynx is concerned, to the above. The cat has plainly very 

 great command over the larynx, and can produce a wide range 

 of tones. The peculiarities of the bray of the ass are owing to 

 voice production both during inspiration and expiration. 



The quality of the voice of 

 most animals appears harsh to 

 our ears, owing probably to a 

 great preponderance of over- 

 tones, in consequence of an im- 

 perfect and unequal tension of 

 the vocal bands; but the influ- 

 ence of the supra-laryngeal caid- 

 ties, often very large, must also be 

 taken into account. 



In certain of the primates, and 

 especially in the howling mon- 

 keys, large cheek-pouches can be p,o. 438.-Lower larynx (Syriruc) of 



iTifln+pfl witVi air frnm tbp InrvTry """ (after Gegenbaur). A, seen 



mnatea wiin air irom me larynx, j^^^ ^jij^. ^ ^^^^ j^^,^ j„ j^^^^ 



and so add to the intensity of the <i^/. muscles concerned in move- 



"^ ments of lower larynx; g, mem- 



note produced by the vocal bands brana tympanlformis interna, 



that their voice may be heard for 

 miles. Song-birds produce their 

 notes, as may be seen, by exter- 

 nal movements low down at the bifurcation of the trachea 

 (syrinx). The notes are owing to the vibration of two folds of 

 the mucous membrane, which project into each bronchus, and 

 are regulated in their movements by muscles, the bronchial 

 rings in this region being correspondingly modified. 



A large numiber of species of fishes produce sounds and in 

 a variety of ways, in which the air-bladder, stomach, intestines, 

 etc., take part. Most reptiles are voiceless, in the proper sense, 

 though there are few that can not produce a sort of hissing 

 sound, caused by the forcible emission of air through the upper 

 respiratory passages. 



Frogs, as is well known, produce sounds of great variety in 



stretching from median surface of 

 either bronchus to a bony ridge 

 (pessulus) which projects at the 

 angle of bifurcation of trachea. 



