SNAKES. 431 
an animal down that slender neck and through those little jaws appears too 
absurd to be entertained for a moment, and even the leg which it has 
grasped appears to be several times too large to pass through the throat. 
But by slow degrees the frog disappears, the mouth of the snake gradually 
widening until the bones separate from each other to some distance, and are 
only held by the ligaments, and the whoie jaw becoming dislocated, until the 
head and neck of the Snake look as if the skin had been stripped from the 
reptile, spread thin and flat, and drawn like a glove over the frog. 
The Serpents, in common with other reptiles, have their bodies covered 
by a delicate epidermis, popularly called the skin, which lies over the scales, 
and is renewed at tolerably regular intervals. Towards the time of changing 
its skin, the Snake becomes dull and sluggish, the eyes look white and blind, 
owing to the thickening of the epidermis that covers them, and the bright 
colours become dim and ill-defined. Presently, however, the skin splits upon 
the back, mostly near the head, and the Snake contrives to wriggle itself 
out of the whole integument, usually turning it inside out in the process. 
This shed skin is transparent, having the shape of each scale impressed 
upon it, being fine and delicate as goldbeater’s skin, and being applicable to 
many of the same uses, such as shielding a small wound from the external air. 
THE first sub-order of Snakes consists of those serpents which are classed 
under the name of VIPERINA. 
All these reptiles are devoid of teeth in the upper jaw, except two long 
poison-bearing fangs, set one at each side and near the muzzle. The lower 
jaw is well furnished with teeth, and both jaws are feeble. The scales of the 
abdomen are bold, broad, and arranged like overlapping bands. The head 
is large in proportion to the neck, and very wide behind, so that the head 
of these Snakes has been well compared to an ace of spades. The hinder 
limbs are not seen. 
In the first family of the Viperine Snakes, called the Crotalide, the face is 
marked with a large pit or depression on each side, between the eye and the 
nostril, The celebrated and dreaded RATTLESNAKE belongs to this family. 
This dreaded reptile is a native of North America, and is remarkable for 
the singular termination to the tail, from which it derives its popular name. 
At the extremity of the tail are a number of curious loose horny structures, 
formed of the same substance as the scales, and varying greatly in number 
according to the size of the individual. It is now generally considered that 
the number of joints on the “ rattle” is an indication of the reptile’s age, a fresh 
joint being gained each year immediately after it changes its skin and before 
it goes into winter quarters. ; ‘ 
The joints of this remarkable apparatus are arranged in a very curious 
manner, each being of a somewhat pyramidal shape, but rounded at the 
edges, and being slipped within its predecessor as far as a protuberant ring 
which runs round the edge. In fact, a very good idea of the structure of 
the rattle may be formed by slipping a number of thimbles loosely into 
each other. The last joint is smaller than the rest, and rounded. As was 
lately mentioned, the number of these joints is variable, but the average 
number is from five or six to fourteen or fifteen. There are occasional 
specimens found that possess more than twenty joints in the rattle, but such 
examples are very rare. 
When in repose, the Rattlesnake usually lies coiled in some suitable 
spot, with its head lying flat, and the tip of its tail elevated in the middle of 
the coil. Should it be irritated by a passenger, or feel annoyed or alarmed, 
it instantly communicates a quivering movement to the tail, which causes the 
joints of the rattle to shake against each other, with a peculiar skirring ruffle 
very much like the sound of the escaping steam of a railway engine. 
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