154 ZOOLOGY. 



and limbs. Many apes of the New Continent (America) 



Sf* 



Fig. 108. Skeleton of the Bat.* 



opossums, &c., have prehensile tails ; amongst reptiles, the 

 chameleon offers the same peculiarity. 



OF THE VOICE. 



296. In certain of the lower animals there exists no 

 trace of this faculty; in insects, the sound produced by the 

 friction of their wings, or of some other tegumentary parts, 

 is a necessary result of their movements, as of flight, for 

 example, and can scarcely be viewed as a phenomenon of 

 expression. But in the higher animals the voice acquires 

 another importance : it is under the direction of the will ; it 

 is more varied, and depends on a totally "different cause ; for 

 in all these, it is caused by the passage of the air through a 

 determinate point of the respiratory canal, disposed in such a 

 way as to cause the air to vibrate. 



297. The larynx (Fig. 31), surmounting the trachea 

 and communicating directly with the pharynx, and by its 

 means with the nostrils and mouth, is the organ of the voice 

 in man and in mammals. It may be felt on the surface of the 



* The bones have the same letters as in Figure 95 : cl, the clavicle; op, 

 the thumb. 



