appeared more sluggish than usual, taking no notice of the worms that were given to it, which at other times it greedily devoured. The skin in some parts of the body appeared loose, and its colour not so lively as before. It began the operation of casting the skin, by loosening that part about the jaws; it then pushed it backward gently and gradually, both above and below the head, till it was able to slip out first one leg and then the other. With these legs it proceeded to thrust the skin as far backwards as they could reach. This done, it was under the necessity of rubbing its body against the gravel, till it was more than half freed from the skin, which appeared doubled back, covering the hinder part of the body and the tail. The animal now bent back its head, taking the skin in its mouth, and, setting its feet upon it, for firmer hold, by degrees drew it entirely off, the hind-legs being dragged out in the same manner that the fore ones were before. On examining the skin it was, in every instance, found to be turned with its inside outwards, but without any breach except at the jaws. These creatures do not, however, like some of the snakes, put off the coverings of the eyes along with the skin; for two round holes always appear where the eyes have been. This operation sometimes occupies near half an hour; and after it is finished the Lizard appears full of life and vigour. If the skin is not taken away very shortly after it is cast, the animal usually swal lows it whole, as it does other food. Sometimes it begins with the head part first; and the tail being filled with air and water becomes like a blown bladder, and proves so unmanageable that it is very diverting to see the pains it costs to discharge these, and to reduce it to a condition to be got down the throat*. Dr. Townson, who had several of these Lizards in a jar for the purpose of trying experiments on their respiration, says that he fed them with worms, and that if they were in the greatest stillness, and a worm was dropped ever so gently among them, they all immediately began to fight, each attacking his neighbour, and seizing it by the head, foot, or tail. This he remarked to be not a contention immediately for the worm, for that often lay for a short time unnoticed, but it seemed to originate in a great acuteness of smell (which in a moment informed them of the presence of their food), and in a singular dullness of their discriminating powers †. Being never seen in winter, these Lizards are supposed to retire into holes or mud, and become torpid. They deposit their spawn towards the end of May or beginning of June, in small clusters, consisting of several palish yellow-brown globules included in surrounding gluten. The larvæ are furnished with fins on each side of the breast, which fall off when the animals attain a perfect state. * Paper of Mr. Baker in Phil. Tran. vol. xliv. p. 529. THE SERPENTS*. THERE is much geometrical elegance in the si nuous motions of the Serpent tribe. Their backbone consists of moveable articulations, and runs through the whole length of their body. The breast and abdomen are surrounded with ribs. Some of the species can make their bodies stiff, and by this means are enabled to spring with great force and velocity on their prey. The bodies of most of the tribes are covered with scales; and Linnæus has endeavoured to mark the species by the number of scaly plates on the abdomen and beneath the tail; the former he denomi nates scuta, and the latter subcaudal squame: but every day's experience tends to prove that these are too uncertain and variable to be depended on. The head is connected to the trunk without the intervention of a neck. The jaws are so formed that the animals are able to swallow bodies as thick and frequently even thicker than themselves. The tongue is slender and cleft. The poisonous Serpents differ from the others in having long tubular fangs on each side of the head, calculated to convey the venom from the bag or receptacle at the base into the wound made by their This is the second Linnean Order of the AMPHIBIA. bite. The principal distinguishing rule in these tribes is, that the venomous Serpents have only two rows of true or proper teeth (that is, such as are not fangs) in the upper jaw, whilst all others have four. A head entirely covered with small scales is also in some degree a character, but by no means, an uni versal one, of poisonous species; as are also scales on the head and body furnished with a ridge or prominent middle line. The number of poisonous Serpents is very few when compared with the whole number of the species. Out of about 230 species described in Systema Nature there are not 40 that have been discovered to possess the poisonous fangs. All the species cast their skins at certain periods; and those of cold and temperate climates lie concealed in a torpid state during winter. The flesh of several of the Serpents is innoxious, and even eaten by the natives of many countries. Some of them deposit eggs, which are connected in a kind of chain; and others produce their young perfectly forined from eggs hatched within their bodies, THE RATTLE-SNAKE TRIBE. THE animals of this tribe, which are very few, are all furnished with poisonous fangs, but their bite is not fatal unless they happen to be much irritated, They are confined to the warmer parts of America, where they prey on the smaller birds, lizards, and insects. They give notice of their approach by the rattle at the end of their tail, which is composed of hollow membranaceous articulations, that annually increase in number till they amount to about forty. The head is broad, and covered with large carinated scales, or such as have a prominent middle line: the snout is rounded and obtuse. Their Linnean generic character is, that they have scuta on the abdomen; scuta and squamæ beneath the tail, and the tail terminated with a rattle. THE BANDED RATTLE-SNAKE*. This, the most dreaded of all the Serpents, is found both in North and South America, where it usually grows to about five or six feet in length. Its colour is yellowish-brown above, marked with broad transverse bars of black. Both the jaws are furnished with small sharp teeth, and the upper one has four large incurvated and pointed fangs. At the base of each is a round orifice, opening into a hollow, that appears again near the end of the tooth in the form of a small channel: these teeth may be raised or compressed, When the animals are in the act of biting, they force out of a gland near the roots of the teeth the fatal juice this is received into the round orifice of the teeth, conveyed through the tube into the channel, * SYNONYMS.-Crotalus horridus. Linn.-Boiquira. La Cepede. -Rattle-snake. Var. |