CATARHINA. 419 



deposits of Nortli America is found the genus Laopithecus, 

 which is stated to have relationships both with the Limno- 

 theridce and with some of the Platyrhine Monkeys of South 

 America, 



Platykhina. 



The section of the Platyrhine Monkeys is exclusively con- 

 fined to South America, and one of its leading characters is 

 to be found in the almost universal possession of a prehen- 

 sile tail ; this being an adaptive character by which the 

 animal is suited to the arboreal life which so many of the 

 South American Mammals are forced to lead. Tliere are 

 neither cheek-pouches nor natal callosities, and there is an 

 additional prsemolar, and sometimes a molar less than in 

 Man and the Old World Monkeys. The nostrils are simple, 

 wide apart, and placed nearly at the extremity of the snout. 



'> o 



O O 



The prsemolars are ^ in number, and have blunt tubercles. 



3 — 3 



The thumbs of the fore-hands are either wanting altogetlier, 

 or, if present, are not opposable, though versatile. 



The fossil remains of Platyrhine Monkeys are only known 

 to occur in South America, to which country all the existing 

 forms are confined. Here, in deposits of late Tertiary or 

 Post-Tertiary age, have been found remains of Monkeys re- 

 ferable to the existing genera Cehus, Callithrix, and lacchus, 

 along with a large form which constitutes the extinct genus 

 Protopithecus, and which is allied to the recent Mycdes. No 

 remains of Platyrhines have hitherto been found in South 

 America in deposits older than the Post-Pliocene, nor in any 

 other country in deposits of Tertiary age. It is possible, 

 however, that the Laopithecus of the North American Mio- 

 cene, above referred to, may be referable to the Platyrhina 

 rather than to the Strcpsirliina. 



Catarhina. 



The third and highest section of the Quadrumana is that 

 of the Catarliina or Old World Monkeys. In this section 

 the nostrils are oblique, and are placed close together, and 



