QUADRUMANA. 603 



maim. In Ateles the tail is long, slender, and powerfully pre- 

 hensile ; and the limbs are very long and slender. The pollex 

 is absent, or is quite rudimentary. In Mycetes there is a bony 

 drum which is formed by a convexity of the os hyoides and 

 communicates with the lar)mx. The voice is thus rendered 

 extraordinarily resonant. The pollex is not opposable, but is 

 placed on a line with the other fingers. 



Catarhina. 



The third and highest section of the Quadrumana is that of 

 the Catarhina or Old World Monkeys. In this section the 

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

 septum narium is narrow. The thumbs of all the feet are 

 opposable, so that the animal is strictly quadrumanous. In 

 Colobus alone the anterior thumbs (pollex) are wanting. The 

 dental formula is the same as in man. viz. : — 



. 2 — 2 I — I 2 — 2 3 — 3 



The incisors, however, are projecting and prominent, and 

 the canines — especially in the males — are large and pointed. 

 Moreover, the teeth form an uneven series, interrupted by a 

 diastema or interval. The tail is never prehensile, and is 

 sometimes absent. Cheek-pouches* are often present, and the 

 skin covering the tubera ischii is almost always callous and 

 destitute of hair, constituting the so-called " natal callosities." 

 With the single exception of a Monkey which inhabits the 

 Rock of Gibraltar, all the Catarhina are natives of Africa 

 and Asia. 



There are three well-marked groups or tribes of the Cata- 

 rhine Monkeys. In the first of these the tail is long, and 

 there are both cheek-pouches and natal callosities. In this 

 tribe is the genus Semnopithecus, all the species of which are 

 natives of Asia and its islands. One of the best-known species 

 is the Sacred Monkey of the Hindoos {SemnopitJiecus entelliis). 

 Closely allied to the Semnopitheci is' the genus Colobus, in 

 which alone, of all the Catarhine Monkeys, the pollex is either 

 altogether absent or totally rudimentary. Closely allied to 

 Semnopithems, also, is the Proboscis Monkey or Kahau (/yffl-^_)'/w 

 nasalis), distinguished by its elongated proboscidiform nose, 

 short pollex, and long tail. Here also come the little Guenons 

 {Cercocebus ssiA Cercopithecus, fig. 234). Also referable to this 



* The cheek-pouches are sacs or cavities in the cheeks, which open into 

 the mouth, and serve to hold any superfluous food. 

 2Y 



