Lemurs, Monkeys, and Apes 
5 
Africa and southern Asia, and are especially abundant in Mada- 
gascar. This great island, which has long been separated from 
the mainland, is at present the peculiar home — perhaps more 
correctly ''refuge" — of the lemurs, where they nourish exceed- 
ingly. They are all small and most hide during the day, coming 
out only at night to feed on leaves and fruits, or sometimes on 
eggs and small animals ; but just before man invaded Madagascar 
many of the lemurs attained a comparatively large size, and some 
may have been of aquatic habits. The skull of the extinct 
Megaladapis insignis, for example, represented by a model in 
Pier-case 3, measures not less than 15 inches in length, and the 
species of Nesopithecus, Palceopropithecus, and Archceolemur , 
represented by several well-preserved skulls, are also large. In 
fact, when a group of animals lives under favourable circumstances, 
and is placed beyond the reach of formidable enemies, its members 
always tend towards much variability and increase of size ; only 
when adversity comes, the larger animals soon die out, while the 
smaller and less conspicuous alone survive. 
The lemurs seem to have disappeared from the northern 
hemisphere at the end of Oligocene times, and were followed in 
the more southern parts, both of Europe and North America, by 
monkeys, which are animals of a distinctly higher grade in their 
brain-development. 
In America monkeys spread as far south as Patagonia, but 
eventually became restricted to the forests of the tropical and 
sub-tropical regions, where they still survive in abundance. They 
are of a peculiar group, differing from all the Old World monkeys 
in the possession of three premolar teeth on each side instead of 
two, the flattening and widening of their nose, and the frequently 
prehensile nature of their tail. Since Miocene times, when they 
were represented in Patagonia by Homunculus, they appear to have 
lived unchanged, and they never produced great apes or made any 
approach to man. Skulls and jaws of Mycetes and Cebus are 
exhibited from the caverns of Brazil (Pier-case 3). 
In the Old World the immediate predecessors of the monkeys 
seem to be represented by some small jaws and teeth of Parapi- 
thecus and Propliopithecus from a Lower Oligocene deposit in Egypt. 
As shown by plaster casts of these fossils in Pier-case 3 they are 
remarkable for the comparatively small size and weakness of the 
canine teeth. Typical modern monkeys, with the canine teeth 
enlarged into weapons, have lived since Miocene times. Portions 
of jaws and teeth of Oreopithecus from the Upper Miocene of 
