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 (Midide) 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 slightly 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 (Af¢eles), 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 Chrysothriz, 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 thin-nosed, while the 
tail is short and not prehensile. 
The catarrhine monkeys (Cercopithecide) walk on all- 
fours ; the body being horizontal or prone ; they have thirty- 
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 furrowed. 
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 monkeys of menageries 
are the macaques (Macacus) of India. All the foregoing 
catarrhine monkeys have a simple stomach, as in man, but 
in the sacred monkey of India (Semnopithecus) and the 
African thumbless Colobus, the stomach is more complex, 
and there are no cheek pouches. 
