464 ORDERS OF MAMMALIA. 



CHAPTER XLII. 

 ORDERS OF MAMMALIA Concluded. 



QUADRUMANA AND BlMANA. 



ORDER XIII. QUADRUMANA. The thirteenth order ot Mam- 

 mals is that of the Quadrumana, comprising the Apes, Mon- 

 keys, Baboons, Lemurs, &c., characterised by the following 

 points : 



The hallux (innermost toe of the hind-limb) is separated 

 from the other toes, and is opposable to them, so that the 

 hind-feet become prehensile hands. The pollex (innermost 

 toe of the fore-limbs) may be wanting, but when present, it 

 also is usually opposable to the other digits, so that the animal 

 becomes truly quadrumanous, or four-handed. 



2 2 3 3 



The incisor teeth generally are - , and the molars - 



3 22' 33 



with broad and tuberculate crowns. Perfect clavicles are 

 present. The teats are two in number, and are pectoral in 

 position. 



The Quadrumana are divided by Owen into three very 

 natural groups, separated from one another by their anato- 

 mical characters and by their geographical distribution as 

 follows : 



STREPSIRHINA. 



This section of the Quadrumana is characterised by the 

 possession of twisted or curved nostrils, placed at the end 

 of the snout. The incisor teeth are generally much modified, 



^ __,_ _ ^ t *y -,- ^ 



and are in number as a rule ; the praemolars are - 



3 3 3 3 



2 2 



or - and the molars are tuberculate. The second digit 

 2 2' 



of the hind-limb has a claw, and both fore and hind feet have 

 five toes each, all the thumbs being generally opposable. In 

 the true Lemurs, all the digits, except the second toe of the 

 hind-feet, are furnished with nails. 



This section is often called that of the Prosimicz, and it in- 

 cludes several families, of which the Aye-Ayes, Pottos, and 

 true Lemurs are the most important. 



No member of the Strepsirhine division of the Quadrumana 

 has as yet been discovered in the fossil condition. When, 



