188 



HIGH SCHOOL ZOOLOGY. 



mouse, while the Lemurs proper are of large size, attaining in the case of 

 the tailless Indri (Lkhanolus) nearly three feet in length. The other 

 Lemurs are smaller in size and provided with a long tail whicb is coiled 

 about them for warmth, while they rest during the day. In Propi- 

 thecus the snout is short as in the Indri, the result being a monkey-like 

 face, while in the ring-tailed lemur (L. catta) and its allies, the snout is 

 prolonged. 



41. However monkey-like certain of tlie lemurs are, they 

 form a decidedly more primitive group than that of the 

 monkeys proper. This is especially noticeable in the sti-ucture 

 of the brain, the cerebellum being left uncovered by the cere- 

 brum in the former group, while, in the latter, the hinder lobe 

 of the cerebrum is so developed as to overlap the cei'ebellum 

 entirely. In this respect, as well as many other anatomical fea- 

 tures, the monkeys agree in structure with Man, and, accord- 

 ingly, they are generally placed together in the order Primates, 

 in spite of the exceptional j^lace which Man otherwise occupies 

 in nature. In all Primates the incisors are f , the inner digits 

 (thumb and great toe) are opposable (except in man, where this 

 is only tnie of the thumb), and all the fingers are nailed, not 

 clawed. The orbits, which have complete bony walls, are di- 

 rected forwards, and the face, in comparison with the Lemuroids, 

 is hairless. 



Apart from ]\Lan, three families 

 of Primates are recognized, two of 

 which are New World groups. 

 Most of the S. Anitn'ican monkeys 

 belong to the Platyrrhini, so called 

 on account of the width of the 

 septum of the nostrils, which 

 % causes these apertures to look 



■.•■5 ■*■ 



^~ outwards. The tail is usually 

 prehensile, assisting in their ar- 

 S^ horeal life in the dense forests 

 ™ ,. , • r. 1 j,v,. . which thev inhabit ; they differ 



Asanexanii>le of thi; Platyrrhini. from both the other families in 



(From Brehru.) 



