THE VOICE. 



formed at the top of the two branches (b,b) of the windpipe (c). 

 each provided with two vocal cords. The different pieces of this 

 apparatus are moved by peculiar muscles, the number of which 

 varies in different families. In birds which have a very mono- 

 tonous cry, such as the gulls, the herons, the cuckoos, and the 

 margansers (fig. 60), there is but one or two pairs ; parrots 

 have three ; and the birds of song have five. 



184. Man alone, of all the animal creation, has the power 

 of giving, to the tones he utters, a variety of definite or arti- 

 culate sound? ; in other words, he alone has the gift of 

 epeech. 



