The Hylæosaurus was another enormous reptile, whose remains were found in the wealden* of Tilgate Forest. This animal appears to have combined some of the features both of the crocodile and of the lizard. It was covered with thick scales, and along the back was a row of long conical bones or spines, resembling the crests we have described as belonging to the Iguanas and Agamas. This animal is supposed to have been a terrestrial, herbivorous reptile, between twenty and thirty feet in length. Altogether it must have been of the most extraordinary reptilian organization. The Megalosaurus was another gigantic lizard, whose remains have been found in the same localities as the preceding. From the teeth, of which numerous specimens have been discovered, and which had a conical, saber-like form, it is inferred that the animal was carnivorous. probably twenty-five to thirty feet long. It was The Plesiosaurus we have already described (page 8, vol. I.); of the Ichthyosaurus there were many species. "These," says Mantell, "had the beak of a porpoise, the teeth of a crocodile, the head and sternum of a lizard, the paddles of a cetacea, and the vertebræ of a fish." Some of the species were of the size of young whales. The bones forming the sternum or chest resemble those of the ornithorhynchus; the paddles are four, and are like those of the turtles. In some species the bones of the fore-paddles are one hundred in number. The general form was like that of the grampus. The skin was destitute of scales. It was evidently carnivorous and aquatic. * Wealden is a term used by English geologists in application to the uppermost series of the strata included in what is called the Oolitic system, that is, the rocks of the secondary formation, of which the Bath stone and Portland stone of England are examples. The term wealden was adopted from the fact that the formation was first observed in the wealds, that is, woods, of Sussex and Kent, in England. The Tilgate Forests are a part of this region. The whole consists of limestone, conglomerate, sandstone, and clay, abounding in the remains of fresh-water and land animals. These are supposed to have been deposited in an estuary or arm of the sea, which once covered this part of England. The Teleosaurus appears to have been a gigantic land animal, resembling the gavials, but with more massive jaws and a stouter form. Its remains are numerous, especially in the wealden of Tilgate Forest; it therefore existed at a period when the fishes were abundant, but the mammals few in number. Its habits appear to have been more strictly marine than those of the gavials, and its powers of swimming and overtaking its prey were greater. It was covered over with imbricated scales, and was perhaps about fifteen feet in length. There were many species, one of which had a skull four and a half feet long, and one hundred and eighty teeth! ORDER 4. OPHIDIA. We now come to an order of reptiles which appear from the earliest ages to have excited a mingled fear and reverence in mankind. In some cases the serpent has been worshiped; in others it has been the symbol of eternity; everywhere it seems to inspire a species of horror in the beholder. In Genesis it is said that "the serpent was more subtle than all the beasts of the field," and therefore the Devil, in seeking to overturn the designs of the Almighty in the creation of man, took upon himself its image. The Brazen Serpent set up in the wilderness by Moses, being looked upon, cured the people which had been bitten by the "fiery serpents" as they journeyed in the wild and rocky regions of Mount Hor; this image is also deemed an emblematic foreshadowing of the Saviour. Serpent-worship appears to have existed alike among civilized and barbarous nations; among the ancient Egyptians it was the object of peculiar reverence, and with the Mexicans it was the very basis of their hideous and bloody religion. Strange ideas respecting this creature are even current in the proverbial language of our day: "wise as a serpent," and "a snake in the grass," though of somewhat contradictory significations, are still common expressions. When we come to consider these creatures, we shall not, perhaps, be surprised that they have ever made a strong impression upon mankind. The great nursery of this reptile race is found in tropical regions. Tangled forests, impenetrable jungles, morasses teeming with luxuriant vegetation, and mouldering ruins overgrown with VOL. II.-49. brushwood and creeping plants, are their favorite places of abode. There they not only exist, but swarm; there the most gigantic of their tribes rears its resplendent form; and there thousands of every size and hue astonish or alarm the passer-by. Some species, slender as whipcord, and of great length, twine around the twigs and boughs of trees and shrubs, their tints amalgamating with the color of the foliage that conceals them, while rapidly and silently they glide even to the tops of the loftiest trees, in chase of insects and of the eggs and young of birds. Others may be beheld by the traveler darting along the ground, crossing his path, and plunging into the midst of the jungle ere his eye can catch their tints, while a loud and angry hiss sufficiently intimates that it is perilous to follow. Many are endowed with the most deadly poisons, while others are of gigantic size and strength. In the Dutch colonies of the East Indies, André Cleyer is said to have purchased of the hunters of the country an enormous serpent, in the body of which he found a deer of middle age, absolutely entire. In another individual of the same species, also examined by this traveler, he found a wild goat, with its horns; and a third had evidently swallowed a porcupine with its quills. He also adds that a woman became the prey of a reptile of the same genus in the island of Amboyna, and that this kind is sometimes kept for the purpose of attacking buffaloes in the kindom of Arracan, on the frontiers of Bengal. We need hardly be astonished at this, when Prince Maurice, of Nassau Siegen, one of the governors of Brazil in the seventeenth century, assures us that he himself was an eye-witness of stags and other bulky animals, and even of a Dutch woman being devoured in this manner. Instances of this kind have, indeed, become common in more modern times. The animals of this order, familiarly called Serpents and Snakes, are characterized by an elongated body, clothed in scales and destitute of limbs, but furnished with a tail. They have hooked, conical teeth, and cold blood like other reptiles; the skin is covered with scales and plates, and this is covered with an epidermis which is frequently cast. They possess the power of fasting a great length of time; they feed on living prey, and always swallow it whole, which they are enabled to accomplish by their faculty of dilating their jaws and bodies to an enormous size. This power is carried to such an extent that the largest species can swallow a bullock whole, though twice as thick as its body, and suffering no other inconvenience than that of lying in a state of torpor while digestion is proceeding. Serpents generally roll themselves up when in a state of repose, with the head in the center, and when disturbed, raise the head before they uncoil the body. They also frequently raise themselves upright, supporting themselves on the tail. They have great freedom of motion, the scales on the belly enabling them to lay hold of fixed objects, and by the alternate elongation of the body, they glide along, often with great celerity. Their usual modes of progression are by a vertical motion, as represented in the preceding engraving, and more frequently by a lateral movement, which enables them to glide rapidly among grass and bushes, as exhibited in the following figure. They are not only able to run on the land, but they swim freely in water, and many species, as we have said, climb trees with facility. Few animals have such variety of locomotion: they can creep, glide, grasp, suspend themselves, erect themselves, leap, dart, bound, swim, and dive. They are mostly oviparous, their eggs being soft, of a yellowish-white color, covered with a leathery skin, and from twenty to thirty in number at each laying. Their senses are not very acute; the eyes are small, and without lids; the tongue is free, forked, and capable of considerable elongation and rapid motion. They are divided by Dr. Gray into two sub-orders, the VIPERINA, or Venomous Serpents, and the COLUBRINA, or Colubrine Snakes, which are for the most part harmless, though some of them are otherwise. These animals are exceedingly numerous, no less than one hundred and fifty species being in the Catalogue of the British Museum. We shall only attempt to describe a few of the most remarkable kinds. THE VIPERINA. The Viperina, so far as known, are all ovo-viviparous; they are also distinguished by the peculiar arrangement of the teeth in the upper jaw. The true maxillary bones are reduced to a very small size, capable of a great amount of motion, and bear a single pair of long curved fangs, which can be laid flat in the mouth during repose, or erected when in action by the agency of peculiar muscles. These are the only teeth supported by the maxillary bones; they are perforated throughout by a slender canal, which communicates with a large gland situated in the head, behind and under the eyes. This secretes the venomous fluid, which passes through a duct to the base of the tooth, and thence through the canal in its interior, until it is injected into the wound made by the bite of the serpent. Its propulsion is effected partly by the contraction of the proper walls of the gland, and partly by the pressure of the muscles of the jaws, which act upon it during their contraction. The poison which is thus injected into the wound mixes with the blood, and is then carried into the circulation, where it speedily produces an injurious effect, giving rise to an altered condition of the blood, which, if the poison be present in sufficient quantity, quickly renders it incapable of supporting life. In fact, a bite from one of the large poisonous snakes of tropical climates is generally fatal, even to man, if the animal be in a vigorous condition, and provided with a good supply of poison; but a bite from a similar snake, after it has nearly exhausted its venom by previous attacks, may give rise to little or no inconvenience. It is remarkable, also, that the effect of the poison of these creatures is very different upon different animals; the coldblooded species in general appear to be almost indifferent to its effects, while most warm-blooded animals soon expire when a sufficient quantity is injected into their veins. Various means of preventing the injurious effects of the bite of these reptiles have been proposed, and the natives of most countries in which they abound have their favorite antidotes for the wounds inflicted by them. The only means, however, upon which it appears that much reliance can be placed, are SECTION OF THE HEAD OF A SERPENT. a, poison fangs; b, poison glands; c, conductor for the poison; dd, muscles of the jaws; e, tendon of the muscles; s, salivary glands. those directed to preventing the poison from getting into the circulation, and of these the principal consist in sucking the wound—either with a cupping-glass or with the mouth, which may be done without the least danger, the poison being quite innocuous when taken internally-cutting out the wounded part, or burning it with a hot iron or with caustic applications. All these remedies must, however, be adopted immediately after the wound has been received; if any time be allowed to elapse the most distressing symptoms make their appearance, and if these can be relieved by the administration of medicines, which, however, appears somewhat doubtful, the patient generally suffers for a long period from the effects of the bite. The Viperina are divided into two families, the Crotalida, of which the rattlesnakes are the types, and the Viperidae, of which the vipers are the types. This family not only contains the rattlesnakes, but a considerable number of other species distributed throughout the warm parts of the earth; they are all particularly distinguished by the presence of a deep pit on each side of the nose, situated beneath, and usually a little behind the nostril. This pit, the purpose of which is still unknown, is lined with small plates. The head is broad and flat, scaly on the crown, and furnished with small shields only on the sides and nose. The teeth are very small, but the poison-fangs are exceedingly large and powerful; and these snakes must be regarded as among the most dangerous of the order. The belly is covered with broad shields. Genus CROTALUS: Crotalus.-This includes the Rattlesnakes, of which there are several species, all belonging to the continent of America. The COMMON or NORTHERN RATTLESNAKE Of the United States, often called Banded Rattlesnake, C. durissus, is of a yellowish or reddish brown, sometimes of a chestnut black, with irregular, rhomboidal, black blotches; head large, flattened, and triangular; neck small; tail short; length from three to four feet, sometimes even as much as seven or eight. Like the other Viperina they produce their young alive. Upon the tail is what is called a rattle, consisting of several horny enlargements loosely attached to each other, and making a loud rattling noise when shaken and rubbed against each other. These rattles generally increase with the age, but not regularly once a year, as is supposed. Two and even four have been known to come in a year, and sometimes several of the rattles drop off; they are seldom over twenty-five in number. The use of these extraordinary appendages seems RATTLE OF TWENTY-FOUR JOINTS. |