ISO GEOGRAPHICAL ZOOLOGY. [part iv. 



other. About this same time (but perhaps not contempo- 

 raneously) Madagascar must have been connected with some 

 portion of Southern Africa, and the whole of the country would 

 possess no otlier Primates but Lemuroidea. After the Mada- 

 j^ascar territory (very much larger than the existing island) 

 had been separated, a connection appears to have been long 

 maintained (proljably by a nortlierly route) between the more 

 equatorial portions of Asia and Africa ; till those higher forms 

 had Ijecome developed, which were afterwards differentiated into 

 Simia, Presbyter, and Ci/nopifhecus, on the one hand, and into 

 I'roglodytcs, Colobus, and Cynoccphalus, on the other. In ac- 

 cordance with the principle of competition so well expounded 

 ])j Mr. Darwin, we can understand how, in the vast Asiatic and 

 African area north of the Equator, with a great variety of 

 physical conditions and the influence of a host of competing 

 forms of life, higher types -were developed than in tlie less 

 extensive and long-isolated countries south of the Equator. 

 In Madagascar, where these less complex conditions prevailed 

 in a considerable land-area, the lowly organized Lemuroids have 

 diverged into many specialised forms of their own peculiar type ; 

 while on the continents they have, to a great extent, become 

 exterminated, or have maintained their existence in a few cases, 

 in islands or in mountain ranges. In Africa the nocturnal and 

 arl)oreal Galagos are adapted to a special mode of life, in which 

 they probably have i&w competitors. 



How and when the ancestors of the Cebidne and Hapalidae 

 entered the South American continent, it is less easy to conceive. 

 The only rays of light we yet have on the subject are, the 

 supposed afiinities of the fossil Ccvnopithecus of the Swiss, and 

 the Lemuravida3 of the North American Eocene, wdth both 

 Cebid?e and Lemuroids, and the fact that in Miocene or Eocene 

 times a mild climate prevailed up to the Arctic circle. The dis- 

 covery of an undoubted Lemuroid in the Eocene of Europe, 

 indicates that the great Northern Continent was probably the 

 l)irthplace of this low type of mammal, and the source whence 

 Africa and Southern Asia were peopled with them, as it was^ 

 at a later period, witii the higher forms of monkeys and apes. 



