274 
CROCODILES AND SNAKES 
so cause its death in a few short minutes, but must either secure it by 
strength of jaw alone, or must overcome it by means of sheer bodily 
strength. Snakes feed upon animals of different kinds, whose bodies 
would seem far too large to be swallowed whole. But the jawbones 
are so loosely fastened together that they can be separated to some 
distance from one another, being then only held together by ligaments. 
The skin and flesh of the neck, too, can be greatly stretched, and so 
the snake manages to get the head of its victim fairly into its mouth. 
By slow degrees it is then worked down the throat by the alternate 
action of the upper and lower tooth-rows, the jaws separating more and 
more widely, and the skin of the neck stretching to such a degree that 
one would think that it must certainly burst. At length, after great 
exertions, the prey is swallowed, the jaws close, and the neck returns 
to its normal size. 
The Frogs.— There is a group of animals which previously was 
classed among reptiles, but which, owing to certain differences in 
their life and structure, are now more properly considered to belong 
to another class, altogether, under the name of Batrachians. Some of 
these are familiar to all of us, the toad and the frog, for instance, being 
very well-known members of the group. 
Now, there is one very important way in which these animals 
differ from all the reptiles. Crocodiles, turtles, lizards, and snakes are 
all of exactly the same form when just born as they are when fully 
mature, the chief difference between the parents and their young being 
in point of size. But this is not the case with the frogs, for, when they 
are first hatched from the egg, they are not like their parents at all, 
and do not become so until they have lived for some little time in the 
world. There is, in fact, quite as much difference between the young 
and the mature frog as there is between a caterpillar and a perfect 
butterfly. 
During the first part of their lives they live in the water just as 
fishes do, breathing water instead of air, but in course of time the 
greater number change their habits altogether, and breathe air itself 
by means of lungs, just as do all the animals about which we have 
hitherto read. 
We all of us know the large jelly-like masses which are to be 
