772 MANUAL OF ZOOLOGY. 



natural groups, separated from one another by their anatomical 

 characters and by their geographical distribution as follows : 



Section A. Strepsirhina. The members of this section are 

 characterised by the nostrils being curved or twisted, whilst 

 the second digit of the hind-limb has a claw. This section 

 includes the true Lemurs and a number of allied forms. It is 

 chiefly referable to Madagascar as its geographical centre ; but 

 it spreads westwards into Africa, and eastwards into the Indian 

 Archipelago. 



Section B. Platyrhina.^^s section includes those Quad- 

 rumana in which the nostrils are placed far apart ; the thumbs 

 of the fore- feet are either wanting, or, if present, are not oppos- 

 able to the other digits and the tail is generally prehensile. 

 The Platyrhine Monkeys are exclusively confined to South 

 America. 



Section C. Catarhina. In this section the nostrils are ob- 

 lique, and placed close together. The thumb of the fore-limb 



Fig. 449. Green Monkey or Guenon (Cercocebus sabceus). (After Cuvier.) 



(pollex), with one exception, is present, and is always oppos- 

 able to the other digits. The Catarhine Monkeys are restricted 

 entirely to the Old World, and, with the single exception of a 

 Monkey which inhabits the Rock of Gibraltar, they are exclu- 

 sively confined to Africa and Asia. It is in the Catarhine sec- 



