220 TlMEHRI. 
bat, but its food consists simply of fruits and insects. 
The true blood-sucking bat (Desmodus rufus) is much 
smaller, and a specimen is shewn in the British Museum 
which was taken by DARWIN in the act of sucking the 
blood of a horse. The bats as a group are distinguished 
by the extreme length of the front limbs, the fingers of 
which are very elongated, and are connected by a thin 
membrane which is continued along the sides of the body 
to the hind limbs, and forms a wing which in fun6lion 
resembles the wing of a bird, though quite different in 
structure. The hind limbs are much reduced in size, but 
serve by its claws to suspend the bats when they are at 
rest, — in the usual position head downwards. 
Of the group of the Primates or monkeys, several 
forms are shown, such as the howler (Mycetes seniculus) 
of roaring repute, the different forms of sakis (Pithecia 
sp.) with non-prehensile bushy tails, the different forms of 
sapajous (Cehus sp.) , together with the sackawinkis and 
marmosets. The curious long-legged spider-monkeys 
and the night-monkeys are not, however, represented. 
Monkeys, as a group, are well characterised by the 
hind-feet being modified to form hands, the first toe being 
opposable to the others ; by the first toe or all the toes 
bearing flat nails instead of claws ; and by the dentition, 
the front teeth or incisors being four in each jaw, as in 
man. The American monkeys are widely separated from 
the Old World forms by several charafters, of which the 
chief is that the nostrils are placed far apart, a thick 
septum separating them so as to give them almost a 
lateral opening, while in the Old World forms the nostrils 
are close together, the septum being thin. The tails, 
moreover, are never prehensile in the Old World forms ; 
