92 NATUBAL HISTOBY OF 



more prominent and dilated, and by containing in its 

 body a cavity capable of holding a large pea. On lay- 

 ing open the posterior part of the larynx, the -two 

 apertures at the base of the epiglottis, and leading to 

 the laryngeal pouches discovered by Camper, were 

 visible. 



The great difference in these organs from the human 

 are the large sacks, which evidently produce the power- 

 ful and deep sounds uttered by so many of this 

 tribe. In the black orang, being carried into the body 

 of the os hyoides, it shows the first indication of struc- 

 ture so peculiarly belonging to the American howlers. 

 In the Siamang, remarkable for the power of voice, 

 the simple sacks are so extensive as to protrude pro- 

 minently to outward view. They prevent the ut- 

 terance of systematic sounds which the other organs 

 might produce, by preventing a power of control over 

 the air. ff Every time that the animal would uttei 

 his cry, these sacks swell, then empty themselves, sc 

 that he is not able, at will, to supply to the differert 

 parts of his mouth the sounds they might articulate.* 



In intellect we consider the quadrumanous animals, 

 notwithstanding what has been written and recorded 

 of many of them, not superior, and in many cases 

 inferior, to others of the animal creation ; it has the 

 same constitutional distinctions, and presents the 

 same great differences, from a true reasoning power. 



* Bicherand, Physiology, p. 424. 



