of the World584 The Living Animals

of other lizards, including tree-climbing varieties, wereventure to approach it. A number introduced to the company of the examples under observation, and until friendly acquaintanceship had been established their advances towards the chamseleons were always repelled. The majority of the chamaeleons lay eggs, but a small number produce living young, as with skinks and other lizards. Examples of the common European and North African species kept by the writer excavated holes in the earth, in which they laid their eggs, and then carefully covered them up again. Unfortunately these eggs were not fertilised. One South African species has been reported to the writer as being in the habit of placing and separately wrapping and fastening up each egg as deposited in the leaves of the tree in which it resided. While Africa and Madagascar represent the head centres of distribution of the fifty odd known species

Photo by JF". Saville-Kent, F.Z.S.] [Milford-on-Sea. of chamseleons, they enter Europe through THE TUATERA OF NEW ZEALAND. the Spanish Peninsula, and extend eastward to Arabia, India, and Ceylon. TheBelongs to an ancient reptile race of which it is the only living survivor. largest known variety, which inhabits Madagascar, attains a length of 15 inches; the smallest pygmy chamseleon of the Cape scarcely measures 2| inches.

THE TUATERA.

That singular reptile found on certain small islands lying to the north-east of New Zealand, and known as the TUATERA, differs in so many structural characters from all other lizards that it is assigned to a separate order. Externally the tuatera does not differ materially in its leathery, granulated, andform from an ordinary lizard. The skin, however, is peculiar for wrinkled texture; there is no trace of external ears; the eyes, adapted for nocturnal vision, have in daylight vertical pupils; and the bases of the toes are united by connecting webs. The deeper internal characteristics include the possession of supplementary so-called abdominal ribs, the presence of which are readily apprehended on handling the living animal. These structures, while absent in ordinary lizards, find their near equivalent in the breastplate of tortoises and turtles. The teeth are not implanted in distinct sockets, but attached to the summits of the jaws, which are developed in a beak-like manner, and in older individuals fulfil, after the manner of a beak, the functions of the worn-out incisor teeth. Photo by W. Saville-Kent, F.Z.S.] [Milford-on-Sea.

Tuateras have been exceedingly scarce A TAME TUATERA. of recent years, and in view of their scientific Is a great acquisition for a greenhouse, feeding on slugs, beetles, and all interest, and the risk of their possible ex- noxious insects. tinction, are now protected by the New Zealand Government. Among the multitudinous gifts of which their Royal Highnesses the Prince and Princess of Wales were recipients during their recently accomplished world-embracing tour, a pair of living tuatera lizards formed one of the most singular and highly prized contributions accepted from the loyal New Zealanders.

Photo by H, 0. F. Spurrdl, Esq.} [Eastbourne.

DARK GREEN SNAKE.

A native of Italy and other countries bordering the Mediterranean. Accredited with a particularly fierce disposition.

CHAPTER V.

SNAKES.

characteristic contour of a snake's body is too familiar to need elaborate description; its leading features are, in fact, so nearly approximated by certain of the legless lizards,THE previously described, that the distinctions between the two can with difficulty be defined. are altogether devoid ofMany of the snake-like lizards, including the Common Blind-worm, external limbs. In some snakes, on the other hand, and notably the large terrestrial Pythons, a spur-like development on each side of the base of the tail represents rudimentary hind legs. The Snakes agree essentially with the Lizards in the character of their scaly covering, the scales, however, being larger on their under-surface and specially adapted, as in the legless lizards, for creeping locomotion. The essential distinctions between the two groups have to it obtains in thebe sought in the structure of the head. The most notable of these, as Snakes, is the very loose manner in which all the bones connected with the jaws are held together, thus providing for the greatest possible distension in the act of their swallowing their prey whole, as is the custom of all ordinary snakes. To achieve this end, the two halves of the lower jaw are not united together at their extremity or chin, as in lizards, but are merely connected with one another by an elastic ligament. In most snakes the bones of the upper jaw and palate are also attached to one another in a similar way.

The eyes of a snake differ in a very marked manner from those of ordinary lizards. No snake possesses movable eyelids. The eye, in compensation, is protected by a transparent is shed with it when the snake castshorny disk, continuous with the general epidermis, and its skin. This feature imparts to snakes that fixed, stony expression of the eyes which undoubtedly contributes very materially towards increasing the feeling of repulsion with which snakes are commonly regarded. A few exceptional lizards, such as the Geckos, have a similar eye-construction, but it is not met with in any of the limbless or snake-like forms. No snakes, again, show any trace of external ear-openings, such structures, on the other hand, is neverbeing distinctly developed in almost all lizards. The head itself of the snake compressed or elevated, as in most lizards, but flattened down and usually wider than the isbody, to which, however, it is united without a distinct neck. The tongue of the snake slender, and terminates in two long, thread-like points; basally it is inserted into a hollow sheath, into or out of which the entire organ can be retracted or exserted at will. The itsomewhat uncanny, flickering action with which a snake, while moving, displays and as were feels its way with its long, forked tongue represents another element which adds to the 585 74

disfavour with which these reptiles are commonly regarded. Among the uneducated even at the present day it is not unusual to hear the tongue, with reference to its peculiar shape and vibrating action, pronounced to be the seat and instrument of the animal's poisonous properties. The swift, silent, stealthy, gliding motions with which, apart from any visible fillorgans of locomotion, a snake slides, as it were, along the ground and over all obstacles to the brink the measure for its condemnation in the estimation of all but the snake-devotee or the naturalist. The locomotion of the snake is, as a matter of fact, one of the most remarkable and beautifully contrived phenomena in animal mechanics. The peculiarly jointed and abnormally mobile ribs constitute the mystic deus ex machina by which the reptile accom-plishes its migration. These ribs articulate in pairs by a single mobile head with their respective segment of the vertebral column. At their opposite extremity they impinge on and are in muscular connection with the broad, slightly overlapping, shield-like scales which clothe the under surface of the body. The rib-muscles, contracting in rhythmical succession, raise the free overlapping edges of the shield-like scales, which, striking against the ground in the same regular order, push the body forward. Adopting an easily comprehensible simile, the snake's body is carried along the ground on the same principle as a paddle-wheel steamer is pushed along the surface of the water, the paddle-boards in the case of the snake being affixed to a long, narrow plane instead of a circular wheel. The poison-fangs of snakes are highly specialised structures, and their presence or otherwise was formerly considered sufficiently distinctive for the separation of these reptiles into two

Photo liy H. G. F. Spurrell, Esq.] [Eastbourne. sharply defined natural series. DARK GREEN SNAKE. More recent investigations Closely allied to the rat-snake of India, and preys in a similar manner on rats, mice, and birds. have, however, shown that such a system of classification is entirely artificial, both venomous and harmless species occurring among groups which are related to one another by essential structural characters. The teeth in the ordinary or harmless snakes are usually represented by two rows of slender, recurved, sharply pointed teeth in the upper jaw, and a single row of a similar character in the lower one. This recurved character of the dentition effectively assists the snake in gorging its quarry whole, nothing once seized by the hook-like teeth having a chance of retreating, the snake itself being unable to eject the prey upon which the teeth have fastened. In the most poisonous series, such as a rattle-snake, there is but a single row of recurved teeth in the upper jaw, and these are the -equivalents of the inner set of the harmless species. Among the most venomous snakes the poison-fangs are tubular in character, the poison being received from the venom-glands at their open base, and discharged at the apex. In other forms the fangs have grooved channels only for the passage of the virus, while in other species there may be an intermediate condition. In all cases the poison-secreting glands are modifications of the ordinary salivary glands of other vertebrate animals. They are situated, one on each side, immediately below and behind the eyes, and are in some instances so abnormally developed as to extend backwards along the sides of the body. Special muscles envelop these glands, strike.and force the poison into the hollow base of the fangs when the mouth is opened to

Photos by Fredk. Doicner & Sons] [ Watford.

A SMALL BOA-CONSTRICTOR SEIZING AND DEVOURING A RAT.

Illustrating the consecutive phases of seizing, strangling, and subsequently gorging the prey, as practised by the largest and smallest members of the class.

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of the World588 The Living Animals

Snakes, like lizards, are most abundant in tropical countries, the Indian and Malay regions in particular being richest in numbers and varieties. The British Islands support but three representatives of the class the ADDER, the COMMON KINGED and the SMOOTH SNAKES this number, by a coincidence, being identical with that of the Lizard Tribe indigenous to the same islands. Many of the smaller species are little over 1 foot long, while the huge Pythons and the Anaconda may attain to or exceed 30 feet. Kegarding their habits, some are purely terrestrial, frequenting the rocks or sandy deserts, or even burrowing beneath the earth's surface. Others are essentially arboreal, many amphibious, and some, like the Turtles among the Chelonians, entirely marine. As with the Lizards, the majority of snakes lay eggs enclosed within a white leathery shell, while with a considerable number the young are brought forth alive. The eggs, deposited in the earth, sand, or among vegetable debris, are usually left to be hatched by the heat of the sun. In the case of the Pythons, however, they are incubated by the parent. of snakes which is usually placed at the head of the series in systematic A small group classifications share the subterranean habits of the Amphisbsenas among the Lizards; and the eyes being rudimentary and functionless, they are commonly known as BLIND-SNAKES. A structural peculiarity which separates these singular reptiles from all other members of the Snake Tribe is the entire absence of teeth from either the upper or lower jaw. The food of the blind-snakes consists largely of ants and the larvae of beetles and other insects which lead a subterranean life. Although spending the greater portion of their existence under- Photo by W. P. Dando, F.Z.S.] [Regent's Park. BOA-CONSTRICTOR READY TO STRIKE. ground, they occasionally The neck, thrown back in one or more loops, can be projected, with immense force and lightning- COme OUt Upon the Surface, like rapidity, to strike or seize an intended victim. SUch migrations more generally taking place during showery weather. About 100 species of blind-snakes are known, and are mostly confined to its tropical countries. One small worm-like form occurs in Greece and the adjacent islands, range extending through a considerable area of South-western Asia.

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