cause it is usually taken in pursuit. As soon as this takes place, the frog ceases to make any struggle or attempt to escape. The whole body and the legs are stretched out, as it were, convulsively, and the snake gradually draws in first the leg he has seized and afterwards the rest of the animal, portion after portion, by means of the peculiar mechanism of the jaws, so admirably adapted for this purpose. When a frog is in the process of being swallowed in this manner, as soon as the snake's jaws have reached the body, the other hind leg becomes turned forwards; and as the body gradually disappears, the three legs and the head are seen standing forwards out of the snake's mouth in a very singular manner. Should the snake, however, have taken the frog by the middle of the body, it invariably turns it, until the head is directed towards the throat of the snake, and it is then swallowed, head foremost." The frog is not only alive during the above process, but often after it has reached the stomach. Mr. Bell says, "I once saw a very small one, which had been swallowed by a large snake in my possession, leap again out of the mouth of the latter, which happened to gape, as they frequently do immediately after taking food."
This species is truly oviparous. Its eggs, from sixteen to twenty in number, attached together by a glutinous secretion, are deposited in some favourable locality, as a dung-hill, and are hatched by the heat developed, or that derived from direct exposure to the sun. In this circumstance it will be seen to differ from the viper, to which we must now return.
The common viper (Pelias berus) is so variable in minor features, especially in colouring, that its varieties have been described as new species. It is more common in Scotland than the snake, and is everywhere abundant in heaths, dry woods, and banks. In many parts of England is is called the adder, for between the adder and viper there is no difference. Its general colour lies between an olive and a red-brown. There is a mark between the eyes, and a zigzag black line running the whole length of the body, with a row of irregular triangular spots on each side. The scales or plates on the head are smaller, and those of the upper parts of the body longer than in the snake.
The great difference exists in the possession by the viper of poison and fangs, and facility in using them. In the upper jaw, instead of a double row of teeth, as in the snake, this reptile possesses two or three long curved fangs, with a tubular passage down them, communicating with the glands that secrete venom at their base, and open at the apex. When not in use these fangs recline backwards upon the jaw, but are instantaneously erected, when required, by the aid of a small muscle. The poison is a tasteless, yellowish fluid, innocuous when swallowed, but venomous when it enters the blood through a wound. When the viper strikes its victim, the pressure on the tooth forces a small drop of the poison from the reservoir at its base, along the tube into the wound. It is well known that if venomous serpents of this kind are irritated and caused to strike at a stick, or some other object for a few times, the store of venom becomes expended, and that afterwards their bite is comparatively harmless, until a new supply of venom has been secreted. If the snake can be regarded as our miniature representative of the boa, the viper deserves to be considered as a little apology for the rattlesnake; the rattle, of course, being excepted.
Like many other poisonous reptiles, the young of the viper are matured in the egg whilst still in the uterus of its parent, and the thin membrane which enclosed them is ruptured at their birth, so that the viper seems to be truly viviparous, as the eggs are never excluded entire. There is a firm belief extant amongst country people, who make no aspirations to science, that the young of the viper, from twelve to twenty in number, when alarmed, rush to their mother, and glide one by one down her throat for security, whence they emerge again when the danger is past. This has been so often and so seriously affirmed, that, however much we may feel disposed to doubt, we are not in a position to deny.
As neither vipers nor snakes are to be seen during the winter months, it is but reasonable to expect that some explanation of this circumstance should be given. Reptiles do not generally like cold weather, therefore they proceed to winter quarters—
In their nest snug and small,
And then they come out in the Spring, poor things.
Vipers and snakes hybernate in company, coiled up and torpid, in hollows at roots of trees, without food or requiring any; and in the spring resume life and activity. During the winter the venomous species secrete no poison, and if aroused and driven to the use of their fangs, appear to be powerless for mischief.
As the aim of our present chapter is to
