368 BRITISH MAMMALS 



America and Australasia had ceased. Therefore, although the 

 South American monkeys reached as far south in that continent 

 as the Rio de la Plata, they never spread into Australasia. 1 



It is possible, also, that in Africa from the basal stock of the 

 Platyrrhines arose the Catarrhines, or Old World apes, dis- 

 tinguished from the New World monkeys by the presence of 

 only two pairs of premolars in the dentition, by the narrow 

 nose, by the structure of the bony supports to the ears, and 

 several other features in the skull. Africa, therefore, may have 

 originated the True Apes, the direct ancestors of man. The 

 competition between the lemurs, on the one hand, and their 

 more perfected descendants, the Platyrrhines and Catarrhines, 

 drove the former southwards and eastwards into that projection 

 of the African Continent which is now the island of Madagascar, 

 leaving at the present day only a few isolated species of lemur 

 on the main continent of Tropical Africa. Madagascar was cut 

 off from Africa by the sea during the Tertiary Epoch, and at a 

 time before it could receive any form of real monkey. Thence- 

 forth Madagascar remained the great home of the lemurs, 

 many genera of which attained extraordinary specialisation. 

 Thus the lemurs originated in North America, but have found 

 their final resting-place in a large island several hundred miles 

 off the east coast of Africa ! 



The Catarrhine monkeys, having originated in Africa, where 

 by far the preponderating number of types are found at the 

 present day, spread northwards to the Mediterranean, Europe, 

 and across Arabia and Syria into Asia. Prior to this migration 

 they were probably sufficiently differentiated to represent the 

 parent types of the genera Semnopithecus^ Afacacus, Cynocephalus, 

 and the sub-family of the anthropoid apes. In Central and 

 Southern Europe the anthropoid apes appear first to have 

 emerged distinctly from the mere monkey, and, together with 



1 The present and Pleistocene distribution of the South American 

 monkeys strongly suggests their African origin. They are most numerous 

 in species in the north-eastern part of the South American Continent (Brazil), 

 though they penetrated as far south as Patagonia. 



