154 The Descent of Man. Part I 



orang, and hylobates, are by most'iiaturalists separated from the 

 other Old World monkeys, as a distinct sub-group. I am awara 

 that Gratiolet, relying on the structure of the brain, does not 

 admit the existence of this sub-group, and no doubt it is a broken 

 one. Thus the orang, as Mr. St. G. Mivart remaiks,"" " is one of the 

 " most peculiar and aberrant forms to be found in the Order." 

 The remaining non-anthropomorphous Old World monkeys, are 

 again divided by some naturalists into two or three smaller sub- 

 groups ; the genus Semnopithecus, with its peculiar sacculated 

 stomach, being the type of one such sub-group. But it appears 

 from M. Gaudry's wonderful discoveries in Attica, that during 

 the Miocene period a form existed there, which connected 

 Semnopithecus and Maoacus ; and this probably illustrates the 

 manner in which the other and higher groups were once blended 

 together. 



If the anthropomorphous apes be admitted to form a natural 

 sub-group, then as man agrees with them, not only in all those 

 characters which he possesses in common with the whole 

 Catarhine group, but in other peculiar characters, such as the 

 absence of a tail and of callosities, and in general appearance, we 

 may infer that some ancient member of the anthropomorphous 

 sub-group gave birth to man. It is not probable that, through 

 the law of analogous variation, a member of one of the other 

 lower sub-groups should have given rise to a man-like creature, 

 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 modification, chiefly 

 in consequence of the great development of his brain ard his 

 erect position ; nevertheless, we should bear in mind that he " is 

 " but one of several exceptional forms of Primates."" 



Every naturalist, who believes in the principle of evolution, 

 will grant that the two main divisions of the Simiadae, 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 considerable extent from each other, would still 

 have formed a single natural group ; but some of the species or 

 incipient genera would have already begun to indicate by their 

 ijivorging 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 den- 

 tition, or in the structure of tneir nostrils, as are the existing 



" ' Transa( t. Z<>Qlog. Soc' vol vi. " Mr. St. R. Mivart, ' Transact 



1887, p. 214. Phil. Soc' 1867, f. 410. 



