SPIDER-MONKEYS. 



159 



tail, with the naked parts of the face flesh-coloured ; the females being of a paler 

 hue. The thumb is totally wanting-. Another varietj', with a distinct rudiment 

 of a thumb, is of a dark brown colour, with white on the sides of the face. 



THE WOOLLY SflOEI! MONKEY (J Uat. sizc). 



The Spider-Moxkf.ys. 



Genus Atelcs. 



The spider-monkeys may be regarded as those members of the group most 

 admirably adapted for a purely arboi'eal life, as is especially shown by their slight 

 bodies, the long prehensile tail, naked below at the end, and the long spider-like 

 limbs from which they derive their popular title. In the rudimentaiy condition, or 

 total absence, of their thumbs, the spider-monkeys may be regarded as holding the 

 same relationship to the sapajous as is presented by the thumbless monkeys (Colohus) 

 of Africa, to the langnn's (Srmvopifhecus) of India: and it is probable that in both 

 instances the abortion of the chundj is due to the uselessness of this digit in a 

 liand adapted to act merely as a kind of hook in swinging from branch to branch. 



