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THE AMERICAN NATURALIST [Vol. XLV 



bling the former in the stout limbs, the latter in its den- 

 tition. Considering the different subfamilies it would 

 appear that the Cercopithecidae originated in southern 

 Europe, that it was fairly successful, and that as a result 

 of this, the family adapted itself in three directions ; first 

 one group left the trees and took to life on the ground, 

 giving rise to Cynocephalus and Macacus; the second 

 group became leaf feeders, and developed a pouched 

 stomach and for some reason also disproportionally long 

 hind limbs, giving rise to Scnnioplthccus and Nasalis of 

 Asia and Colobus of Africa : while those remaining in the 

 trees and changing but little are Cercopithecus and Cer- 

 cocebus of Africa. 



The differentiations took place in the Miocene and are 

 fundamentally based on food supplies. Those forms 

 which had developed strength enough to defend them- 

 selves, their fore and hind limbs being approximately 

 equal in length, and their food including insects, lizards, 

 frogs, etc., as well as all sorts of vegetable life, like 

 leaves, fruit, blossoms, etc., came down from the trees. 



The terrestrial forms which continued to live in the 

 forests make the genus Macacus, or macaques, which 

 during the Pliocene spread pretty well all over Europe, 

 even up into England, and also into western Asia where 

 they still live. In the Pleistocene some representatives 

 of the genus went with the great wave of migration from 

 southern Asia into Africa, but they have become extinct 

 in that continent except for one species, the Barbary ape. 

 Those members of the group which left the woods and 

 took to the more open country developed great strength 

 and powerful jaws and are the baboons (Cyuoccphahts) 

 These too originated in southern Europe and migrated 

 during the Pliocene eastward into Asia, and during the 

 Pleistocene on down into Africa, to which continent they 

 are now confined. 



The second subfamily of the Cercopithecidae are the 

 langurs (Semnopithecus, Nasalis and Colobus) which, 

 while remaining largely arboreal, have specialized as her- 



