QUADRUMANA. 633 



hands are either wanting altogether, or, if present, are not 

 opposable, though versatile. 



The Platyrhine Monkeys are divided into the two sections of 

 the Hapalidce. and Cebida. 



Fam. i. HapalidcB. In this family the number of teeth is 

 the same as in the Old World Monkeys and in Man, but 

 there is an additional praemolar on each side of each jaw, and 

 a molar less. According to Owen, the dental formula of the 

 Marmoset is 



= 32. 



2 2 I I 3 3 22 



The molars, however, are tuberculate, and though the num- 

 ber of teeth is the same as in the Catarhine Monkeys, in their 

 other characters the Marmosets are genuine Platyrhines. The 

 hind-feet have an opposable hallux with a flat nail, but all the 

 other toes are unguiculate, and the pollex is hardly opposable. 

 The tail is long, but is not prehensile. 



The Hapalidcz are all small monkeys, mostly about as big 

 as Squirrels, and they are exclusively South American, occur- 

 ring especially in Brazil. The best-known species is the 

 common Marmoset (Hapale penicillata), but several species are 

 domesticated and kept as pets. 



Fam. 2. CebidcR. In this family are all the typical Platyrhine 

 Monkeys, in which the dentition differs from that of the Hap- 

 alidce in having an additional molar, so that the molars are the 

 same as in the Catarhina and in Man, but the praemolars are 

 more numerous. The dental formula is 



fc; ,1=1; ^3=3 3-3 

 22 i i 3-3 33 



There .are neither cheek-pouches nor " callosities ;" and the 

 face is usually more or less naked, though sometimes whis- 

 kered. The tail is long, and is mostly prehensile ; though in 

 rare instances it is non-prehensile, and has its extremity clothed 

 with hairs. The thumb of the fore-hand may be wanting, and, 

 if present, is not opposable. All the fingers are furnished with 

 flat nails. Their diet is miscellaneous, consisting partly of in- 

 sects and partly of fruit. 



The Cebidcz are exclusively confined to the warmer parts of 

 South America, in the vast forests of which they are met with 

 in large troops, climbing amongst the trees. The Spider 

 Monkeys (Ateles), the Howling Monkeys (Mycetes\ the Ca- 

 puchin Monkey (Cebus\ and the Squirrel Monkey (Calltihrix), 

 may serve as typical examples of this section of the Qiiadru- 



