47 



the unguiculate limb such a modification in the size, shape, 

 position, and direction of the innermost digit that it can be op- 

 posed, as a thumb, to the other digits, thus constituting what is 

 properly termed a ' hand.' Those Unguiculates which have 

 both fore and hind limbs so modified, form the order QUAD- 



RUMANA. They have - incisors, and - - broad tuber- 

 2 2 o o 



culate molars ; perfect clavicles ; pectoral mammae ; vesicular 

 and prostatic glands ; a discoid, sometimes double, placenta. 

 The Quadrumana have a well-marked threefold geographical 

 as well as structural division. 



The Strepsirhines are those with curved or twisted tenni- 



Q Q 



nal nostrils, with much modified incisors, commonly - - ; 



o o 



o q n n 



premolars - - or in number, and molars with sharp 



o o 2 2 



tubercles : the second digit of the hind limb has a claw. 

 This group includes the Galagos, Pottos, Loris, Aye-Ayes, 

 Indris, and the true Lemurs; the three latter genera being 

 restricted to Madagascar, whence the group diverges in one 

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

 Archipelago. 



The Platyrhines are those with the nostrils subterminal 



q p 



and wide apart ; premolars - - in number, the molars with 



O' O 



blunt tubercles ; the thumbs of the fore-hands not opposable 

 or wanting ; the tail in most prehensile ; they are peculiar to 

 South America. 



The Catarhines have the nostrils oblique and approximated 

 below, and opening above and behind the muzzle : the pre- 



2 2 



molars are - in number; the thumb of the fore-hand is 



opposable. They are restricted to the Old World, and, save 

 a single species on the rock of Gibraltar, to Africa and Asia. 

 The highest organized family of Catarhines is tailless, and 

 offers in the Orang, Chimpanzee, and Gorilla, the nearest 

 approach to the human type. 



