The famous Tic-polonga of Ceylon (Daboia elegans) is also widely diffused over India and Burmah. It is beautifully marked with three rows of white-edged, oblong, brown spots. Occasionally the spots forming the middle row are connected like the beads of a necklace, whence the name Cobra monil (literally Coluber moniliger), applied to the young of this Viper by the Indo-Portuguese, and now corrupted into "Cobra de Manilla," which bears the reputation of being a highly poisonous Snake of diminutive size; it attains, however, to a length of nearly five feet, the tail then measuring about eight inches, with considerable thickness of body. It is nocturnal, and preys chiefly on Mice. In Burmah this formidable Viper is dreaded almost as much as the Hamadryas. It has been obtained in the Himalayas at an elevation of 5,500 feet, at Almorah, and elsewhere. Mr. Theobald has known one to kill a Bull-terrier in twenty minutes. The D. xanthina is a second species of this form inhabiting Asia Minor.
Fig. 21.—The Horned Puff-adder (Clotho cornuta).
The genus Clotho consists of the terrible Puff-adders of Africa, of which there are at least four or five species. Among the best known of them are the ordinary Puff-adder (C. arietans), and the Berg-adder (C. atropos), of the Cape colonists. The Rhinoceros Puff-adder, C. nasicornis, of Guinea, has the scales over the nostrils of the male produced into a long recurved spine; and in the Horned Puff-adder, C. cornuta, of South Africa, there is a group of small horn-like scales over each eye. Examples of the Common and of the Rhinoceros Puff-adders may generally be seen in the reptile house of the London Zoological Gardens. The last mentioned is a huge Viper of wondrous beauty, both of colouring and in the complex pattern of its markings, especially as seen when it has newly shed its epidermis; but the aspect of its surprisingly broad, flat, and triangular-shaped head unmistakably betokens its terrific powers. Its head is remarkably massive. One peculiarity of the Puff-adders is that they sometimes hold on to their victim by their long fangs. Thus, of the common C. arietans Sir A. Smith remarks that "although generally inactive, it is by no means so when attacked—its movements are then bold and energetic, and when once it seizes the obnoxious object, it retains its hold with great determination, and some considerable exertion is often necessary to detach it."[18] The traveller Burchell remarks of this Snake that "its venom is said to be most fatal, taking effect so rapidly as to leave the person who has the misfortune to be bitten no chance of saving his life, but by instantly cutting out the flesh surrounding the wound. Although I have often met with this Snake," he adds, "yet, happily, no opportunity occurred of witnessing the effects of its poison; but, from the universal dread in which it is held, I have no doubt of its being one of the most venemous species of Southern Africa. There is a peculiarity which renders it more dangerous, and which ought to be known to every person liable to fall in with it. Unlike the generality of Snakes, which make a spring or dart forward when irritated, the Puff-adder, it is said, throws itself backwards, so that those who should be ignorant of this fact would place themselves in the very direction of death, while imagining that by so doing they were escaping the danger. The natives, by keeping always in front, are enabled to destroy it without much risk. The Snakes of South Africa, as of Europe, lie concealed in their holes in a torpid state during the colder part of the year. It is, therefore, only in the hottest summer months that the traveller is exposed to the danger of being bitten." Dr. Gray refers doubtfully to this genus both the Echidna inornata of Sir A. Smith, and the E. mauritanica of Duméril and Bibron, from Algeria; likewise a Peruvian species named Echidna ocellata by Tschudi, which is the only known instance of a member of this family inhabiting the New World. The appellation Echidna, however, belongs properly to the Porcupine Ant-eaters of the class Mammalia.
Fig. 22.—The Unadorned Puff-adder (Clotho inornata).
The species of Cerastes and of Echis have the nostrils much smaller than the preceding, and are Vipers of less formidable size. In the two species of Cerastes, or Horned Viper, the eyebrows of the male bear commonly a sort of horn. C. Hasselquistii is common in Egypt, and the other, C. Richii, inhabits Tripoli. Of Echis there is one species in Egypt and North Africa—E. arenicola, and another in India—E. carinata. The latter grows to about twenty inches long, of which the tail measures two inches and a third. These Vipers commonly lie half-buried in the sand, which they much resemble in colour. They feed upon Centipedes (Scolopendra), and no case is known of their bite having proved fatal.
The remaining Viperidæ have the head more or less shielded. They are divided by Dr. Gray into Vipera (with two European species, not found in Britain—V. aspis from the Alps, and V. ammodytes from the countries bordering on the Mediterranean);—Pelias, which contains only the Common British Adder, P. berus; Sepedon, with one species only, from South Africa, S. hæmachates; Causus, with also only one African species, C. rhombeatus; and finally, Acanthopis, founded on the Death-adder of the Australian colonists, A. antarctica, which is the only member of the family Viperidæ known to inhabit Australia, where the Poisonous Colubrine Snakes are so numerous. It is also the only known species the scales of which are smooth or not keeled. It seldom exceeds thirty inches in length, and varies a good deal in colour. Like other Viperidæ it is sluggish in its movements, but when irritated it flattens itself out generally in the form of the letter S, turning round to one side or the other with astonishing rapidity, but never jumping at its enemy or throwing itself backward, as the Puff-adders are described to do. The Death-adder is found in almost every part of Australia northward of the thirty-sixth parallel of south latitude.]
The Common Adder (Pelias berus), is not improbably the Εχις of Aristotle, and the Vipera of Virgil, as it is the Manasso of the Italians, the Adder of the country-people in England and Scotland, and the Vipère of France. It is found in all these countries, and in Europe generally.
