Fig. 19.—Fer-de-lance (Trigonocephala mycalæ).
The Fer-de-lance (C. lanceolatus) is met with in Martinique, Santa Lucia, and in the little island of Boquin, near St. Vincent. It attains to a length of nearly six feet; its colour is not always yellow, sometimes it is greyish, and even marbled with brown; the head, which is large, is remarkable for a triangular space, the three angles of which are occupied by the muzzle and the two eyes.
This space, raised at its front edge, represents the head of a lance, large at its base and slightly rounded at the summit. On each side of the upper jaw, one, sometimes two, and even three, fangs are visible; all of which the animal makes use of for the purpose of wounding and discharging his venom. Of the poison fangs of the Fer-de-lance, Professor Owen remarks, "that they (in common with the Rattlesnake and Viper) are coated with a thin layer of a sub-transparent and minutely cellular cement. This disposition of the dentinal tubes is obedient to the general law of verticality, and the external surface of the tooth can be exposed to no other pressure than that of the turgescent duct with which it is in contact." It feeds on Lizards and the smaller Mammals, especially Rats, but it is capable of killing large animals, such as Oxen. The Negroes working among the sugar-cane, and soldiers in the Martinique service, often become victims to the Fer-de-lance. This Snake is, unfortunately, very prolific, and its venom is so subtle, that animals stung by it die three hours, twelve hours, one day, or several after the accident; but their death is certain. The wound produces extreme pain, and is immediately followed by more or less livid swelling; the body becomes cold and insensible, the pulse and respiration become slower, the head becomes confused, coma appears, and the skin turns bluish; sometimes extreme thirst and spitting of blood are experienced, and paralysis attacks the whole system.
Another species is known in Brazil as the "Jararaca" (C. brasiliensis), and there is a third in the same country, the C. bilineatus; a fourth, C. elegans, is believed to be from the west coast of South America; and a fifth, C. atrox, inhabits from Demerara to Mexico. All of them are most highly formidable and dangerous Snakes, which are held in especial dread.
The ten or more species of Trimeresurus occupy their place in the woodland districts of tropical Asia and its islands. In them the hinder labial shields are the smallest. The head is triangular, covered above with small scales, except the foremost part of the snout and the superciliary region, which generally are shielded; body with more or less distinctly keeled scales, in from seventeen to twenty-five series. Body and tail of moderate length, prehensile. These reptiles are more or less arboreal, as is indicated by their prehensile tail, and by their green or varied coloration. "In general," remarks Dr. Günther, "they are sluggish, not attempting to move out of the way, and as they very closely resemble the branch on which they rest, they are frequently not perceived until they prepare to dart, vibrating the tail, and uttering a faint hissing sound, or until they have struck the disturber of their rest. Accidents caused by them, therefore, are not of uncommon occurrence, and it is a fortunate circumstance that comparatively few of them attain to a size of more than two feet, so that the consequences of their bite are less to be dreaded than that of various other poisonous Snakes. Indeed, numerous cases are on record which show that the symptoms indicating a general effect on the system were of short duration, extending only over from two to forty-eight hours, and confined to vomiting, retching, and fever. After the pain and swelling of the bitten member or spot have subsided, the vicinity round the wound becomes discoloured, mortifies, and is finally thrown off as a black, circular slough, after which health is speedily restored. The bite of larger specimens, from two to three feet long, is more dangerous, and has occasionally proved fatal; so that the greatest care should always be observed in the immediate treatment of the patient. When roused, these Snakes are extremely fierce, striking at everything within their reach; and Cantor states that in the extreme of fury they will fix their fangs in their own bodies. Frogs, small mammalia, and birds form their food, and I have never found a Lizard or Snake in their stomach."
Three or more of the species inhabiting India and Burmah are of a beautiful leaf-green colour, which changes to dull blue after long immersion in spirit. The commonest of them, T. carinatus, varies remarkably in colouring, however, in the Andaman and Nicobar Islands; if, indeed, the species be quite the same. These grow to over three feet in length, of which size they are sufficiently formidable. The kindred genus, Peltopelor, is founded on a single species inhabiting the mountains of Southern India, P. macrolepis, which is remarkable for the very large scales with which its head and body are covered. Lachesis, with two species, is another kindred genus in South America, in which the end of the tail has four rows of scales underneath. The Calloselasma rhodostoma is a very formidable reptile of this same series, which inhabits the Malay countries. It has a remarkably broad head, and grows to three feet or more in length. Dr. Günther states that "it is one of the most beautiful and most dangerous of venemous Snakes. Feeding on frogs, it frequents grassy plains, and approaches gardens and human dwellings. Kuhl was eye-witness to a case where two Men, bitten by one and the same Snake, expired five minutes after." Another Malayan species is known as the Atropos acouba. The genus Halomys is characteristic of the fauna of Central Asia, the species being found in Tartary, on the northern side of the Himalayas, in China, in Japan, and in Formosa. One of them occurs in the Western Himalaya, at an altitude of 9,000 feet, and another has been referred to this genus from the mountains of Southern India. The "carawalla" of Ceylon (Hypnale nepa) is likewise found on the mountains of Southern India. It is a small species, but a good deal dreaded, although, remarks Dr. Günther, "its bite is but exceptionally fatal to Man, and in such cases death does not occur before the lapse of some days. There is always every hope of restoring the patient by a timely application of the proper remedies." Its crown is more shielded than is usual with Snakes of this family, and it varies much in colouring.
The rest of the Crotalidæ are American, and consist of the famous Rattlesnakes and their immediate kindred. In the genus Cenchris the tail ends with a spine, and the tip of the tail has several rows of scales beneath. The well-known "Copperhead" (C. contortrix) belongs to this genus, and the black "Water Viper" (C. piscivorus). The last has bred repeatedly in the London Zoological Gardens, and is rather a large species, of very aquatic propensities. "The Copperhead," according to Dekay, "is a vicious reptile, and its venom is justly dreaded, being considered as deadly as that of the Rattlesnake; and an instance is recorded in which a Horse, struck by one of these reptiles, died in a few hours. Its motions are sluggish, and when approached it assumes a threatening aspect, raising its head and darting out its tongue. It chiefly occurs in pastures and low meadow grounds, feeding on Field-mice, Frogs, and the smaller disabled birds." The poison of the black Water Viper is equally to be dreaded.
The true Rattlesnakes have the tail furnished with the extraordinary appendages at its tip which will be described presently. According to differences in the shields and scales covering the head, Dr. Gray arranged them into three genera—Crotalophorus, with three species; Uropsophus, with one; and Crotalus also with one, C. horridus, which appears to be the only one known in South America. Of the common Northern Rattlesnake (Uropsophus durissus), Dekay remarks that, "although furnished with such deadly weapons, the Rattlesnake can scarcely be termed a vicious animal, for he rarely strikes unless almost trodden upon. When suddenly disturbed, he throws himself into a coil, and warns the aggressor by rapidly vibrating his rattles, which, however, can scarcely be heard beyond the distance of a few yards. This is most usually the case, but they occasionally strike without the slightest warning. At the moment the Snake strikes, he ejects the venom forcibly into the wound. In an instance of a very large Rattlesnake from Florida (C. horridus), which was irritated, he struck violently against the iron wire on the side of the cage, and spurted the venom to the distance of three feet."[16] The fibulæ, or rattles, seldom exceed fifteen in number, and are rarely so many.]
The common Northern Rattlesnake sometimes attains to six feet in length, the middle being about the size of a man's leg; the colour of the back is grey, mixed with yellow. Upon this foundation extends a longitudinal row of black spots, bordered with white; towards the muzzle the flat head is covered with six scales larger than the others, and disposed in three transverse rows, each formed of two scales. The males are smaller, much more brightly and less darkly coloured than the other sex. The very long and visible fangs are situated in front of the upper jaw. The scales on the back are oval, and raised in the middle by a bone which extends in the direction of their greatest diameter. The underpart of the body is furnished with a single row of large plates. The Rattlesnake owes its name to a remarkable peculiarity in its structure; the extremity of the tail is furnished with small horny cells, articulated one into the other. When the animal advances these little capsules resound slightly, like the dry husks of beans which still retain their seeds, thus giving notice of the approach of this terrible enemy. The sibilant rattle of these appendages is not very loud, but it may be heard about thirty paces off, and announces the approach of the reptile while it is still at that distance.