276 
CROCODILES AND SNAKES 
speed by means of a series of leaps, very like those of the kangaroo 
upon a smaller scale. The tongue of the frog also is very curiously 
formed, in order to enable it to capture the insects upon which its 
owner feeds. 
When an insect is seen, the frog darts out its tongue, which it 
does with almost the rapidity of lightning, touches it with the tip, which 
is moistened by the very sticky saliva, and draws it back again as 
rapidly as it was thrust out. The fly, of course, adheres to the tip, 
and is carried at once into the throat, owing to the structure of the 
tongue, when it is swallowed without difficulty. The tongue of the 
toad is formed in just the same manner, and is used in exactly the 
same way. 
It is rather a curious fact that the frog always seems to calculate 
the exact distance to which the tongue must be thrust out, the tip reach¬ 
ing to just the required spot, and picking off the victim in the neatest 
possible manner. The whole action is so extremely rapid that the 
movement of the tongue can hardly be seen, and the fly appears to a 
spectator to vanish almost as if by magic. 
The Tree Frog ,—There are some of the frogs which are great 
climbers as well as swimmers, and which are able to cling without dif¬ 
ficulty to the lower surfaces of leaves and branches. The feet of 
these frogs, which are known as tree frogs, are formed very much 
like those of the gecko, the toes being furnished with sucker-like pads, 
which adhere tightly to any surface against which they are pressed. 
One of the commonest of the tree frogs is of a bright green color, and 
so is almost invisible when sitting upon a leaf unless it is looked for 
very carefully indeed. 
