190 THE DESCENT OF MAN. [Part I. 



resembling the higher anthropomorphous apes in so many 

 respects. No doubt man, in comparison with most of his 

 allies, has undergone an extraordinary amount of modifi- 

 cation, chiefly in consequence of his greatly-developed 

 brain and erect position ; nevertheless, we should bear in 

 mind that he " is but one of several exceptional forms of 

 Primates." 13 



Every naturalist, who believes in the principle of 

 evolution, will grant that the two main divisions of the 

 Simiada3, namely the Catarhine and Platyrhine monkeys, 

 with their sub-groups, have all proceeded from some one 

 extremely ancient progenitor. The early descendants of 

 this progenitor, before they had diverged to any con- 

 siderable extent from each other, would still have formed 

 a single natural group ; but some of the species or incipi- 

 ent genera would have already begun to indicate by their 

 diverging characters the future distinctive marks of the 

 Catarhine and Platyrhine divisions. Hence the members 

 of this supposed ancient group would not have been so 

 uniform in their dentition or in the structure of their 

 nostrils, as are the existing Catarhine monkeys in one way 

 and the Platyrhines in another way, but would have 

 resembled in this respect the allied Lemurida? which differ 

 greatly from each other in the form of their muzzles, 14 and 

 to an extraordinary degree in their dentition. 



The Catarhine and Platyrhine monkeys agree in a 

 multitude of characters, as is shown by their unques- 

 tionably belonging to one and the same order. The many 

 characters which they possess in common can hardly 

 have been independently acquired by so many distinct 

 species ; so that these characters must have been inherited. 

 But an ancient form whicli possessed many characters 



13 Mr. St. G. Mivart, « Transact. Pbil. Soc.' 1867, p. 410 



14 Messrs. Murie am 

 Soc' vol. vii. 1869, p. 5 



14 Messrs. Murie and Mivart on the Leniuroidea, ' Transact. Zoolog, 



