558 SPIDER MONKEYS CHAP. 
the most typically arboreal of American monkeys. The use of 
the prehensile tail can frequently be studied in living examples 
in the Zoological Society’s Gardens. With this “ fifth hand” the 
Monkey feels for a place to grasp, and securely twists its tail 
round, moving it with the greatest ease from point to point. 
When the tail is being thus used it is carried erect over the head. 
The fact that this genus possesses no functional thumb is thought 
Fic. 265.—Spider Monkey. Afeles ater. x +)s. 
to be associated with the extreme perfection of its adaptability to 
an exclusively arboreal life. The hand without a thumb can 
act as an equally efficient hook for suspending the body; and 
What is useless in nature tends to disappear. These Monkeys 
have a wide range, extending from Mexico in the north to 
Uruguay in the south. There are ten species. The flesh of 
many Monkeys is eaten not only by natives but by Europeans ; 
but the Spider Monkeys are said to furnish the most sapid food 
of all. 
The Howling Monkeys, genus J/ycetes, have also received the 
appropriate generic names of Alowatta and Stentor. The former 
of these two names, indeed, is that which should properly be 
applied to the genus. But MJycetes is perhaps better known. 
The “ howling” is produced by saccular diverticula of the larynx, 
larger than those of other American Monkeys, such as Afeles, 
where, however, they are also developed. The hyoid bones, too, 
