THE CAPUCHINS. 205 



Man-like of all the Apes; in some species the nails of the 

 digits are compressed laterally. 



In the skull the cranial portion exceeds the facial. 

 Professor Mivart observes that in this group the facial part 

 is relatively smaller than in many of the higher Old World 

 Apes. The skull has no external bony canal (or meatus) to 

 the ear ; and its frontal bones possess large air-cavities. In the 

 Capuchins the incisor teeth are erect, and are always shorter 

 than the canines. The molars are four-cusped, and have, on 

 their crowns, two transverse ridges and the oblique ridge, already 

 described in the Lemuroidea^ from the front inner cusp to the 

 hind outer cusp. These animals have also one milk-molar tooth 

 more than in Man. 



The outer surface of the main brain {cerebrum) is almost as 

 much convoluted as in the Old World Apes. 



The Capuchins range from Costa Rica to Paraguay, and are 

 represented by about eighteen species. They are very gentle 

 and docile animals. 



F. Cuvier observes in his " Histoire Naturelle des Mam- 

 miferes," that of all the Quadrumana — indeed, of all the 

 Mammals— there are none so difficult to characterise as the 

 Capuchins of America, whose colours vary almost with every 

 individual. No two authors agree in the number of species 

 the genus contains. Brisson recognised three, Linnaeus four, 

 Gmelin six, Buffon two, and George Cuvier supposed it possible 

 that they all belonged to but one species. Two causes help to 

 produce this diversity of opinion ; one is, as remarked above, 

 the natural disposition which these animals have to vary, and to 

 become lighter or darker in colour according to circumstances, 

 and the other is the extremely close relationship that exists 

 between the different species of the genus. Observations, how- 



