166 



STUDIES, SCIENTIFIC AND SOCIAL 



CHAP. 



ordinary tails, either long or short ; and, 3rd — the Mar- 

 mosets, very small creatures, with sharp claws, long tails, 

 which are not prehensile, and a smaller number of teeth 

 than all other American monkeys. Each of these three 

 groups contain several sub-grouj^s, or genera, which often 

 differ remarkably from each other, and from all the 

 monkeys of the Old World. 



We will begin with the Howling Monkeys (genus 

 Mycetes), which are the largest found in America, and 

 are celebrated for the loud voice of the males. Often in 

 the great forests of the Amazon or Oronooko a tremen- 

 dous noise is heard in the night or early morning, as if 



Fig. 33.— skull of howleb {Mycetes se^iiculvjt). 



a great assemblage of wild beasts were all roaring and 

 screaming together. The noise may be heard for miles, 

 and it is louder and more piercing than that of any other 

 animals, yet it is all produced by a single male howler 

 sitting on the branches of some lofty tree. They are 

 enabled to make this extraordinary noise by means of an 

 organ that is possessed by no other animal. The lower 

 jaw is unusually deep, as shown in the accompanying 

 figure, and this makes room for a hollow bony vessel 

 about the size of a large walnut, situated under the root 



