MAMMALIAN ORDERS. 



291 



180 



direction to the continent of Africa, in the other to the Indian 

 Archipelago. The Platyrhines are Quadrumana with the nostrils 

 simple, subterminal, and wide apart ; premolars 3^3 in number, the 

 molars with blunt tubercles, 

 fig. 178 ; the thumbs of the 

 fore-hands not opposable, or 

 wanting ; the tail in most pre- 

 hensile ; they are peculiar to 

 South America. The Cata- 

 rhines have the nostrils oblique 

 and approximated below, and 

 opening above and behind the 

 muzzle : the premolars are ^ 

 in number, fig. 179; the 

 thumb of the forehand is op- 

 posable. They are restricted 

 to the Old World, and, save 

 a single species on the rock 

 of Gibraltar, to Africa and 

 Asia. The hio-hest oro-anised 

 family of Catarhines is tail- 

 less, and offers in the Gorilla, 

 or, as some contend, the Sia- 

 mang, fig. 180, the nearest 

 approach to the human type. 



In all the tailless Apes the 

 pelvic limbs are short, and, 

 like the longer pectoral ones, 

 are organised for grasping. 

 The pelvis is long and nar- 

 row; the spine shows one 

 curve, and articulates mth 

 the hinder part of the skull. 

 There is a sexual distinction 

 in the teeth, the canines being 

 lono; and laniariform in the 

 males. All Quadrumana are 

 clothed with hair. The oldest 

 known species of the Qua- 

 drumanous order are of mio- 

 cene date. 



The structural modifica- 

 tions in the genus Homo, — sole representative of the Archencephak. 



u 2 



Quadrumauous skeleton, Siamang {Ilyluhates 

 syndactylus) . 



