THE TROPICAL FOREST 101 
marmosets, which occur only in the tropical forests of 
South and Central America. These animals are very 
squirrel-like in appearance, and show much fewer 
adaptations to the arboreal life than the higher Pri- 
mates, in spite of the fact that they spend their lives 
among the trees. Thus the fingers and toes, except the 
great toe, have pointed claws instead of nails, the hind 
legs are larger and better developed than the front 
ones, and the great toe is very small. The tail is non- 
prehensile. In the absence of the special adaptations 
shown by their allies, the animals climb like squirrels 
rather than like monkeys—that is, they do not grip 
the branches and swing freely from one to another, 
but stick in their claws and climb along the branch on 
all fours. The diet consists of fruits and insects. 
The lowest members of the Primates are the lemurs, 
which show some marked peculiarities of distribution, 
as well as of structure. They are entirely absent from 
the New World, and in the Old World have apparently 
been pushed far to the south by the development of 
better organized forms, or by the attacks of carnivores, 
for all lemurs are very helpless animals. Existing 
lemurs occur in the tropical forests of Africa, in the 
forests of the south-eastern region of Asia, an area 
which contains many strange and primitive animals, 
and finally in the island of Madagascar. In Africa and 
Asia they are few in number, apparently in individuals 
as well as in species, and are always small in size. In 
Madagascar there are more than thirty species, and the 
individuals are abundant in every wood. Here also 
the animals reach a relatively large size, the largest 
being about two feet in length, and, as the number of 
species suggests, they show adaptations to varying con- 
ditions of life. The number of species and differentia- 
