272 
CROCODILES AND SNAKES 
and are secured by the legs in the meanwhile. Sometimes nets are 
used to catch the smaller ones, and harpooning is also resorted to. 
But the prime object is to capture the turtle alive for the markets of 
the great towns of the world. 
The Geckos are very numerous in warmer countries, and such 
is their familiarity with man that they do not hesitate to introduce 
themselves into his habitations, where they render an all-important 
service by devouring flies, spiders and other insects. They themselves 
are kept within limits by the birds of prey, such as the owl and the 
hawk, which feed upon them greedily. 
These lizards are enabled to glide along ceilings or steep walls, 
owing to the construction of the soles of their broad feet. All the 
toes are considerably broadened at the edges, and their under surface 
is divided into a number of scales or layers, from which exudes a 
sticky fluid. They are also provided with sharp, crooked, retractile 
claws, like those of a cat, and these assist them greatly in climbing 
trees. During the day the geckos generally lurk in some dark corner 
or crevice; but at dusk they sally forth in search of prey, running along 
the steepest walls with wonderful swiftness, and venting a shrill, quick 
noise by smacking their tongue against the palate. 
The Snakes are a very large and important order of reptiles. 
They may be divided into two groups, the one consisting of those 
which are poisonous, and the other of those which are not. By far the 
greater number of snakes have no limbs at all, while those members 
are so small in the few which possess them that they are not of the 
least use in enabling their owner either to glide or to climb. And so 
snakes move principally by means of their scales, which overlap one 
another, and which can be raised at will so as to take a firm hold of 
the ground. 
The first necessity for a poisonous snake is the poison. This is 
always found in two glands in the head, corresponding to the saliva 
glands in higher animals. Fatal though it is in its effects when intro¬ 
duced into the blood of the victim, this poison is quite harmless if 
swallowed, and you might drink the poison of a viper without being 
injured by it at all. 
Many people think that the forked tongue of a snake is poisonous, 
