DISTRIBUTION OF MONKEYS 453 



disposition, and have a visage which presents an open 

 facial angle. 



The Old World apes, as just observed, are far more 

 diversified amongst themselves, than are those of the 

 New World. They form, in the first place, two widely 

 distinct groups or sub-orders. Pithecidae and Lemurs, 

 and comprise about 125 species, divided into twenty- 

 one genera. The Lemur group contains a remarkably 

 great diversity of forms ; this is shown by their being 

 naturally divisible into four families ^, and twelve genera, 

 although containing only twenty - five species. Their 

 teeth are very irregular in number and position, but 

 never correspond with those of the Pithecidae or 

 Cebidse. These four families, in structure, are more 

 widely separated from each other than are the two Ameri- 

 can groups of the same denomination. The Lemurs also 

 contain a number of anomalous or isolated forms, which, 

 by their teeth, number of teats, and other features, con- 

 nect the monkeys with other and lower orders of the 

 mammal class ; namely, the Rodents, the Insectivora, 

 and the Bats. All the typical Lemurs, which constitute 

 the great majority of the family, inhabit exclusively the 

 Island of Madagascar. 



The Pithecidae are divisible into three groups, which 

 again are much more distinct from each other than the 

 subordinate groups of Cebidae. These are the Anthro- 

 poid section, to which some zoologists consider man him- 

 self belongs, comprising the Gorilla, the Chimpanzee, the 

 Orangs and the Gibbons ; the Guenons (which, in their 

 forms, tempers, and habits, resemble the Cebidae), and 

 lastly, the Baboons, whose extreme forms — the dog-faced 

 species, with nose extending to the tip of the muzzle — 

 seem like a degradation of the monkey type. There is 

 nothing at all resembling the Anthropoid apes and the 

 Baboons existing on the American continent. The 

 Guenons, too, have only a superficial resemblance to 

 American monkeys ; for they have all thirty-two teeth, 

 nostrils opening in a downward direction (instead of on 

 the sides, like the Cebidae and Marmosets), and are, more- 

 over, linked to the Baboons through intermediate forms 

 (Macacus), and the possession of callosities on the breech, 

 and other signs of blood-relationship. 



^ True Lemurs, Tarsiens, Aye- Ayes, and Galeopitheci. 



