620 ZOOLOGY. 



hind feet, and resting on the same plane, serving as a paw ; 

 the teeth are sharply tubercled, and the nails, except those of 

 the great toe, are claw-like. The cerebral hemispheres are 

 nearly smooth, though relatively large. Jacchus and Midas 

 are the typical genera, inhabiting South America. While 

 the marmosets (Mididm) have but thirty-two teeth, in the 

 true platyrrhine monkeys there are thirty-six teeth ; there 

 being an additional molar on each side of each jaw, and the 

 thumb is shghtly opposable to the fingers (though a true 

 thumb is wanting in the spider monkeys). The New "World 

 monkeys also have long prehensile tails, so useful in climb- 

 ing as to be sometimes called a fifth hand, as seen in the 

 spider monkeys (Ateles), in which the tail underneath is 

 naked and very sensitive. The skull varies greatly in the dif- 

 ferent genera, as does the brain, which in Ghrysothrix, etc., 

 is nearly smooth, while in Cebus the hemispheres are nearly 

 as much convoluted as in the catarrhine apes. (Huxley.) 



The monkeys of the Old World intergrade with the apes, 

 and are thus more specialized or highly developed than 

 those of the New World. The septum of the nose is narrow, 

 hence they are said to be catarrhine or thiu-nosed, while the 

 tail is short and not prehensile. 



The catarrhine monkeys {Gercointliecidce) walk on all- 

 fours ; the body being horizontal or prone ; they have thirts'- 

 two teeth, as in man, though the canines are large and 

 sharp ; the thumb is well developed, and they are truly 

 quadrumanous ; the skull has a comparatively large facial 

 angle, and the hemispheres of the brain are well fun-owed. 

 They have highly-colored, naked callosities over the ischiatic 

 bones, and cheek-pouches for the temporary reception of 

 the food. Of the baboons, with their dog-like muzzles and 

 short tails, the mandrills are the most noticeable, with their 

 white beards, scarlet lips, and blue cheeks ; they are less 

 arboreal than the macaques of Asia, running about over 

 rocks on all-fours. The common monkej^s of menageries 

 are the macaques (Macacus) of India. All the foregoino- 

 catarrhine monkeys have a simple stomach, as in man, but 

 in the sacred monkey of India {SemnopitJiecus) and the 

 African thumbless Colobus, the stomach is more complex, 

 and there are no cheek pouches. 



