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ANIMAL LIFE IN TEE TROPICAL FORESTS 
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inhabit the tropics, and they probably increase in numbers 
towards the equator. A rich vegetation and a due propor- 
tion of moisture and sunshine seem favourable to them, as 
shown by their great abundance and their varied kinds at 
Para and in the Aru islands — places which are nearly the 
antipodes of each other, but which both enjoy the fine equa- 
torial climate in perfection, and are alike pre-eminent in the 
variety and beauty of their insect life. 
Three peculiar forms of lizard may be mentioned as 
specially characteristic of the American, African, and Asiatic 
tropical zones respectively. The iguanas of South America 
are large, arboreal, herbivorous lizards of a beautiful green 
colour, which renders them almost invisible when resting 
quietly among foliage. They are distinguished by the 
serrated back, deep dew-lap, and enormously long tail, and 
are one of the few kinds of lizards whose flesh is considered 
a delicacy. The chameleons of Africa are also arboreal 
lizards, and they have the prehensile tail, which is more 
usually found among American animals.. They are excessively 
slow in their motions, and are protected by the wonderful 
power of changing their colour so as to assimilate it with 
that of immediately surrounding objects. Like the majority 
of lizards they are insectivorous, but they are said to be 
able to live for months without taking food. The dragons 
or flying lizards of India and the larger Malay islands are 
perhaps the most curious and interesting of living reptiles, 
owing to their power of passing through the air by means of 
wing-like membranes, which stretch along each side of the 
body and are expanded by means of slender bony processes 
from the first six false ribs. These membranes are folded 
up close to the body when not in use, and are then almost 
imperceptible ; but when open they form a nearly circular 
web, the upper surface of which is generally zoned with red 
or yellow in a highly ornamental manner. By means of this 
parachute the animal can easily pass from one tree to another 
for a distance of about thirty feet, descending at first, but as it 
approaches its destination rising a little so to reach the tree 
with its head erect. They are very small, being usually 
not more than two or three inches long, exclusive of the 
slender tail ; and when the wings are expanded in the sun- 
