Chapter III: The Order of Lizards.--Saurians (1)

This is the second order of the great section of Scaly Reptiles (_Squamata_), as distinguished from the Shielded Reptiles (_Cataphracta_). The name Saurian, +Sauros+, given by Aristotle to the genus of Lizards, has been more comprehensively applied to a group of Reptiles which have the body elongated, covered with scales, or having the skin rough like shagreen. They have, for the most part, four feet, the toes of which are furnished with hooked claws; their eyelids are movable, and their jaws armed with encased teeth; they have a distinct tympanum, a heart with two auricles and a single ventricle, sometimes partially valved, having sides and a sternum. They are not subject to metamorphosis, and, finally, they are furnished with a tail.

["By far the greater number of the Saurians," writes Dr. Günther, "are easily distinguished from the other orders of reptiles by their elongated form, by their movable thorax covered with skin, by the presence of legs, and by their general integuments, which are either folded into scales, or granular, or tubercular, or shielded; still, there are many Saurians which, at a superficial glance, might easily be taken for members of the preceding order--that of the Snakes; and it cannot be denied that there is a gradual transition from one of these orders to the other. On the part of the Saurians, we allude to those which have no externally visible limbs, and which combine with a greatly elongate, cylindrical body, the peculiar kind of locomotion we observe in Snakes. Yet the greater affinity of these reptiles to the ordinary Lizards is indicated by another character, which is in intimate connection with their mode of life. The Snakes, having movable maxillary bones, and mandibles not joined by a symphidis, are enabled to swallow other animals of apparently greater bulk than their own. In the Saurians the maxillæ are fixed and immovable, and the mandibles are joined by an osseous suture, so that the cleft of the mouth can be dilated only in the usual vertical direction. Moreover, in these limbless Saurians we always find bones of the shoulder hidden below the skin, whilst no trace of them can be discovered in the true Snakes. The motions of some Lizards are extremely slow, while those of others are executed, with very great, but not lasting, rapidity. Many of them have the power of changing their colours, which depends on the presence of several layers of cells loaded with different pigments; these layers the animal compresses by more or less inflating its lungs, whereby the changes in the coloration are effected."

Dr. Günther does not follow Dr. Gray in arranging all true reptiles into the two grand divisions of Shielded Reptiles (_Cataphracta_) and Scaly Reptiles (_Squamata_), but he includes the _Crocodilidæ_ among the Saurians as a first grand division of them--_Emydosauri_, and the other Lizards constitute his second grand division of them--_Lacertini_. These latter are again primarily divisible according to the structure of the tongue. Thus, in the series of _Leptoglossa_, the tongue is elongate, forked, and exsertile, much as in the Ophidians; in that of _Pachyglossa_ the tongue is short, thick, attached to the gullet, and is not exsertile; and in the _Vermilingues_ it is Worm-like, club-shaped in front, and very exsertile.

The various genera of Saurians which have either not a trace of external limbs, or have them more or less diminutive and rudimentary--either the usual two pairs or one pair only, and in the latter case sometimes the fore and sometimes the hind pair being deficient--are included among the _Leptoglossa_, or the series which have a forked and protrusile tongue; and, so far as is practicable, we will commence by noticing the different serpentiform genera; only, in a classification which is not confessedly superficial, it will be found that the various Snake-like Saurians appertain to several distinct natural families, most of the other genera belonging to which have, in sundry cases, limbs that are well developed. Some of them, therefore, will have to be noticed as the different families to which they belong are successively treated of; and there will yet remain the curious serpentiform family of _Amphisbænidæ_, which Dr. Gray refers to his grand series of Shielded Reptiles (_Cataphracta_).

The same naturalist divides the _Leptoglossa_ into two tribes, which he styles _Geissosaura_ and _Cyclosaura_; and, as constituting particular division of the former, he includes under it the family _Typhlopidæ_, which Dr. Günther refers--as we have seen--to the order of Ophidians. In the series of _Geissosaura_, the scales of the belly and (almost always) of the back and sides are quincuncial, rounded, and imbricate; the tongue is narrow, short, flat, and but slightly forked; and the head is of a conical shape, and is covered with regular shields.

Of the families thus characterised, some only have distinct eyelids, as the families _Acontiadæ_, _Ophiomoridæ_, _Sepsidæ_, and _Scincidæ_; while others have the eyelids rudimentary and the eyes exposed, as the families _Lialisidæ_, _Aprasiadæ_, _Pygopodidæ_, and _Gymnopthalmidæ_. In the _Acontiadæ_ the nostrils are placed in the enlarged rostral plate, with a longitudinal slit behind. The form of the body much resembles that of our common Orvet, or Blind-worm, and their limbs, when present, are so rudimentary that they can aid little in locomotion. One genus, _Acontias_, is without limbs, and the eyes are furnished with a lower lid, while the upper eyelid is rudimentary. Of this, one species, _A. meleagris_, inhabits South Africa; and another, _A. Layardii_, has been discovered in Ceylon. The genus _Nessia_ has four rudimentary limbs, and the rostral shield is large, sub-conical, and depressed. In one species, _N. monodactyla_, the limbs are diminutive, the posterior placed far apart from the anterior, all being very short, weak, and undivided into toes. In another, _N. Burtoni_, each foot is divided into three minute toes. Both species are peculiar (so far as known) to Ceylon, and the habits of this family are much the same as those of our common Orvet (_Anguis fragilis_).

The family of _Ophiomoridæ_ is founded on a single genus and species, _Ophiomorus miliaris_, which inhabits North Africa. As remarked by Dr. Gray, this reptile seems to be intermediate to the _Acontiadæ_ and the _Scincidæ_, and makes it appear as if the large rostral shield of the former was formed of the united rostral, supra-nasal, and nasal shields of the present family, and of the _Scincidæ_. It has an elongate, cylindrical body, without external limbs, and the ears are hidden under the skin; the eyes are distinct, with valvular eyelid; and the scales of the body and somewhat elongate tail are hexagonal.

The _Sepsidæ_ differ from the preceding, and also from the great family of the _Scincidæ_, by having the nostrils placed in the front edge of a small shield, in a notch at the hinder side of the rostral plate, which latter is rather large and square. The eyes are distinct, the lower eyelid scaly, or with a transparent disk. Body fusiform or sub-cylindrical, elongate. These reptiles burrow in dry sand, and are peculiar to the anciently-known continents and certain islands. Some have a wedge-shaped head, with prominent rostral plate. Of these the genus _Sphenops_ has more developed limbs, each dividing into four toes; and the only species, _S. sepsoides_, inhabits Egypt and other parts of North Africa. _Sphenocephalus_ has a more slender and elongate shape, and the limbs are placed more distantly apart; the anterior minute, and fitting into a groove, the posterior as large as in _Sphenops_, and each of them having but three toes, of which the innermost and next are sub-equal, and the outer much shorter. The only known species, _S. tridactylus_, is common in Afghanistan. In _Scelotes_ the anterior limbs disappear altogether; and the only known species, _S. bipes_, inhabits South Africa. Other genera have a pyramidal head, with the rostral plate erect, and rounded in front. Such are the five following, each founded on a single species:--_Gongylus ocellatus_, from North Africa and the borders of the Mediterranean; _Thyrus Bojeri_, from the Mauritius; _Amphiglossus astrolabi_, from Madagascar; _Seps tridactylus_, from the south of Europe and north of Africa; and _Heteromeles mauritanicus_, from North Africa. The last has only two toes to the fore-feet, three to the hind; and _Seps_ has three toes to each foot, while the other three genera have five to each foot. In general these animals are found in dry and elevated spots, where they hide themselves in the sand or under stones.

The _Scincidæ_ have the head covered with shields, which are symmetrically arranged. Tongue slender, free, extersile, terminating in two pointed lobes. Scales on the back rounded, quincuncial, imbricate; those on the belly similar to those on the back and on the sides. No fold across the throat or along the side; no femoral or inguinal pores. Tail generally long, rounded, fragile. Eyes and eyelids well developed. Nostrils in a separate plate, between the frontal and labial shields. Generally four limbs, moderately developed, sometimes feeble or hidden below the skin. The species of this family are exceedingly numerous, and inhabit almost every part of the tropical regions, some extending into the temperate zones. They are thoroughly land Lizards, preferring dry ground, and hiding themselves in the sand, under stones, fallen leaves, &c., very few of them entering the water. They do not attain to any considerable size, only a few species of Australia and the West Indies growing to the thickness of a man's wrist, and exceeding a foot in length. Some of them are viviparous, others deposit from eight to twelve globular eggs. Dr. Gray divides them into the sub-families of _Scincinæ_, or those which have the scales thin, smooth, and neither striated nor keeled; the nostrils in a single smooth plate, without any lunate groove behind; and the tail round, tapering, unarmed; and _Tropidophorinæ_, or those which have the scales thick, bony, rugous, striated, and with one or more keels upon each of them; the rostral plate rounded in front, and the body fusiform, with well-developed limbs, which terminate always in the full complement of toes. A few species of the _Scincinæ_ have no external limbs, thus approximating in their appearance to certain of the burrowing Ophidians.]

The Orvet, or Blind-worm, _Anguis fragilis_, is small, cylindrical in shape, about eleven or twelve inches in length, and having the exterior appearance of Snakes. The scales which cover the body are small, smooth and shining, being red in the middle, and edged with white, of a silvery yellow on the upper part, and dusky beneath; the sides somewhat dusky brown, and the throat slightly marbled with white, black, and yellow. Two larger spots appear, one above the muzzle, the other upon the back of the head; from this point two blackish longitudinal rays start, which extend to the tail, as well as two other nut-brown rays, which start from the eyes; the markings vary, however, in different countries, and probably with age and sex.

The Orvet is found in woods and dry, sandy, and stony wastes. They are timid, harmless creatures, retiring into holes and concealing themselves in moss at the foot of trees to hide themselves from observation. They feed upon worms, insects, and the smaller mollusks. Although perfectly harmless, the country-people are strongly prejudiced against them, believing their bite to be a deadly poison. This animal is extremely brittle. Laurenti and others assert that when captured it throws itself into a position of such rigidity that it sometimes breaks in two, and that a smart blow of a switch will at any time divide it.

[There are little-known species of _Anguis_ in India and South Africa, which are at least provisionally so considered, and certainly do not differ essentially; and next we come to forms in which the limbs are successively more developed. Such are the _Ophiodes striatus_ of Brazil, which has two short, flattened, undivided, and one-pointed limbs, corresponding to the usual hind pair; the _Brachymeles bonitæ_ of the Philippines, in which there are two pairs of short and rudimentary limbs, the fore bearing two minute claws, while the hind are undivided; _Venira bicolor_, of the same archipelago has very short limbs, the fore and hind being placed distantly apart, but in this genus all have five distinct toes; _Chiamelea lineata_, from some part of India, and _Hagria Vosmaërii_, from Bengal, are kindred forms which conduct to the genus _Eumeces_, the species of which are very numerous, and spread over nearly all the different countries between or near the tropics, and in certain of them (as the Burmese _E. anguinus_) the limbs are still remarkably diminutive, and (as in _E. isodactylus_ of Cambodia) the fore and hind limbs are placed very far apart, the body and tail being long and anguiform. In various other species of _Eumeces_, however, the proportions are more those of an ordinary Scink, as again in the kindred genera _Mabonia_ and _Plestiodon_, which are widely distributed.

In other series of Scinks, the distinctions of which are far from being conspicuous, we again have limbless genera, or nearly so, as the Australian _Soridia lineata_, which has one pair of small, posterior, undivided extremities; while in another Australian form, the _Rhodona punctata_, the anterior pair of limbs are simple and undivided, while the hinder divide into two unequal toes, and the two pairs of limbs are situate as distantly apart. And thus we may continue to trace the successive gradations, in sundry genera, until we arrive at the _Scincus officinalis_ of North Africa, a well-known reptile, the geographical range of which extends eastward into Afghanistan, and which was formerly in considerable request for its supposed medicinal properties. Indeed, this notion still prevails in Hindustan, into which country dried specimens of both this reptile and of _Sphenocephalus tridactylus_ (p. 101) are brought by Afghan traders, and are sold in the bazaars. Both of these are Sand Lizards, which burrow into the sand with great rapidity.

We now come to the _Tropidophorinæ_, or second sub-family of Scinks indicated by Dr. Gray (_vide_ p. 102), which have always well-developed limbs, the body only moderately elongated, and the scales variously keeled. Several species of larger size appertain to this series, as the _Cyclodus gigas_ of Australia, and the curious Stump-tail Lizards, _Trachydosaurus rugosus_ and _T. asper_, of the same insular continent, which latter have most prominently rugous scales, and the tail literally appearing like the short and abrupt stump of one. _Egernia Cunninghami_ and _Tropidolesma_ (of different species) are other comparatively large Australian Lizards; and examples of most of those that have been mentioned may generally be seen alive in the London Zoological Gardens, where the _Cyclodus gigas_ has bred and proves to be viviparous. Of the species of _Euprepes_, of which several inhabit the Indian region, some (as the very common _E. rufescens_) are viviparous, and others (as _E. multicarinata_) are oviparous. These have three more distinct, though not prominent, keels upon each scale; and the different species inhabit both the Old World and the New, as well as Australia. The Galliwasps (_Celestus_) of the West Indies, and sundry other genera, do not greatly differ. Of _Tropidophorus_, which has exceedingly rugged scales, the species inhabit the Indo-Chinese countries, and one (_T. cocinsinensis_) is found likewise in the Philippines; while of another (_T. Berdmorei_), in Burmah, Mr. Theobald remarks that "its scales are dull and lustreless, and the coloration peculiar for a Scink. It harbours under half-immersed stones, and enters the water and gravel freely." In several of this family of Lizards the scales are beautifully iridescent, and many of them show longitudinal pale or white lines, or are otherwise variegated.

Nearly akin to the extensive family of _Scincidæ_, there are three small families (as classed by Dr. Gray), the species of which are peculiar to Australia. They have small, undivided, posterior limbs only, or are quite limbless. These families are the _Lialisidæ_, founded on three or more species of a single genus, _Lialis_; the _Aprasiadæ_, founded upon one species only--_Aprasia pulchella_, which is limbless; and the _Pygopodidæ_, comprising the two genera _Pygopus_ and _Delma_, the former containing two, the latter only one ascertained species. The _Gymnopthalmidæ_ constitute still another small family, quadrupedal, but with the limbs small and weak. Of seven genera referred to it, five are Australian, one is European, and one belongs to South America. _Ablepharus pannonicus_ is a small Lizard of this family, inhabiting Eastern Europe, with a congener, _A. bivittatus_, in the Caucasus; and _Gymnopthalmus lineatus_ inhabits Brazil and the Island of Martinique.

In the second tribe of _Leptoglossa_, entitled _Cyclosaura_, the scales of the belly are square, in cross bands; those of the back and tail are rhombic and imbricate, or circular and subgranular; the tongue is lengthened, and more or less conspicuously furcate; and the eyes are diurnal, having two valvular lids. The limbs are generally well developed; but in several genera they still are more or less rudimentary, or even absent.

There are four small families in which the sides are rounded and covered with scales like the back. Of these, that of _Chamæsauridae_ is founded upon the South African _Lacerta anguina_ of Linnæus, now _Chamæsaura anguina_, which has the limbs quite rudimentary. In the American families of _Cercosauridæ_, _Chirocolidæ_, and _Anadiadæ_, the limbs are moderately developed, and have each five toes. The two last-mentioned families are founded each upon a single species, _Chirocolus imbricatus_ and _Anadia ocellata_; and the other contains the two genera _Circosaura_ and _Lepisoma_--of which the first comprises some two or three species only. All of these reptiles have exceedingly long tails, though not so inordinately long as in the _Lacertidæ_ of the genus _Tachydromus_.

Certain other families have a distinct longitudinal fold, covered with small granular scales on each side. These are the families _Chalcidæ_, _Holaspidæ_, and the more extensive one of _Zonuridæ_. The _Chalcidæ_ have the head covered with regular many-sided shields, and the lateral fold is indistinct; limbs small and rudimentary, and the hind feet are undivided in the genera _Chalcis_ and _Bachia_, with three tubercles in place of toes in _Microdactylus_, and with four clawed toes in _Brachypus_. Each of these genera is founded on a single species, and all are doubtless peculiar to the New World. The _Holaspidæ_ is also founded on one species only, the _Holaspis Guentheri_, which again is supposed to be South American. It has four well-developed limbs, a double row of plates along the back and upper surface of the tail, and the latter organ is curiously serrated laterally.

The _Zonuridæ_ constitute a considerable family, to which some eighteen or twenty genera are assigned, and which present considerable modification of form. The ears are distinct, whereas in the _Chalcidæ_ they are hidden under the skin. The head is pyramidal, or depressed, and covered with regular many-sided shields; eyes with two valvular lids. Limbs mostly well developed, but short in some, and rudimentary, or even wanting in the so-called "Glass-snakes" which constitute the sub-family _Pseudopodinæ_. There is no external trace of them in the North American Glass-snake, _Ophisaurus ventralis_; and in the Old World genus, _Pseudopus_, there is only one pair, posterior, rudimentary, and undivided. These reptiles are long, and serpentiform in shape: whilst in other Saurians the whole skin of the belly and of the sides is extensible, the extensibility is limited in the "Glass-snakes" to a separate part of the skin; and, as Dr. Günther remarks, "the scaly covering of the upper and lower parts is so tight that it does not admit of the same extension as in Snakes and other Lizards; and the _Pseudopus_, therefore, could not receive the same quantity of food in its stomach as those animals, were it not for the expansible fold of the skin running along each side of its trunk." One species of _Pseudopus_, the _P. Pallasii_, inhabits Asia Minor and the south-east of Europe; and there is another, _P. gracilis_, in the Indo-Chinese countries (or those lying eastward of the Bay of Bengal). A second sub-family, _Gerrhonotinæ_, is peculiar to America, and consists of more ordinarily-shaped Lizards, which are ranged in four genera. Together with the _Ophisaurus_, or American Glass-snake, they are the only known _Zonuridæ_ that inhabit the New World. The great mass of this family and all of its most characteristic species are African, and these are arranged by Dr. Gray under the sub-families _Cicigninæ_ and _Zonurinæ_. In the first of these sub-families the tail is smooth, or unarmed, and in the second it is spinous. The Cordules, _Cordylus_, _Zonurus_, &c., are very characteristic Lizards chiefly of Southern Africa, several species of which have been figured by Sir Andrew Smith. They are mostly of shortish form, and the neck is more or less spinous; the body-scales in some (as _Zonurus cataphractus_) being extraordinarily rugous. These Lizards squeeze themselves into crevices in the rocks, in which they hold on so firmly by their nuchal spines that it is next to impossible to dislodge them, the tail commonly giving way at once if it be attempted to pull them forth by means of it.

The family of _Lacertidæ_, comprising our ordinary European Lizards, have no longitudinal fold along the sides, but generally one across the throat; the tail is very long, rounded, with its scales arranged in rings, being also fragile; the head is covered with shields, which are symmetrically arranged; scales on the back granular or rhombic; on the sides granular; on the belly largely quadrangular or rounded, and arranged in cross-bands; eyes diurnal, with eyelids; the tympanum distinct; limbs always four, and well developed. This group of Lizards has no representative in America or (so far as known) in Australia.

The sub-family of _Tachydrominæ_ is included by Dr. Gray in the family _Zonuridæ_. These are Asiatic Lizards, with a most inordinate length of tail, the fore and hind limbs being not placed distantly apart, as in the various anguiform Lizards already treated of--there is an indistinct collar, and the toes are not serrated or keeled. Two genera have been distinguished, _Tachydromus_ and _Tachysaurus_, the latter founded on a Japanese Lizard, _T. japonicus_. At least three species are known of _Tachydromus_, two of which inhabit China, _T. septentrionalis_ and _T. meridionalis_; the third belonging to the Indo-Chinese countries, _T. sex-lineatus_. In an example of the last, measuring fourteen inches long, the tail occupies eleven inches and a half. It is the longest-tailed creature that we have any knowledge of, in proportion to its other parts; indeed, something quite wonderful to behold and muse over.

The rest of the _Lacertidæ_ are chiefly from Africa and the south of Europe; there are probably more of them to be discovered in Middle Asia, and only three or four species are known to inhabit the Indian region. Fifteen or more genera are recognised. In temperate Europe (inclusive of the British Islands) two species are common--the _Zootica vivipara_ and the _Lacerta agilis_. The former, as its name imports, is viviparous, whereas the other genera belonging to the family are (so far as known) oviparous. Others occur in the south of Europe.]

The common Grey or Sand Lizard (_L. agilis_), sometimes attains the length of from eight to ten inches, of which the tail occupies more than half. These little inoffensive creatures, so common in Southern Europe, are slender and active; their movements are so rapid that they escape the eye as quickly as a bird. They require a mild temperature, and seek shelter among ruins. When the sun strikes with its meridian force upon a wall, they may be seen basking in its rays, enjoying themselves delightedly upon the heated surface. They seem to be pervaded with the blessed warmth, and mark their pleasure by soft undulations of the tail. It is commonly said that the Lizard is the friend of Man, since far from flying at his approach, they seem to regard his appearance with great complacency. They pass the winter at the bottom of small holes which they have hollowed out of the earth, where they become torpid. At the commencement of spring they issue from their hiding-place, and each seeks its mate; they go in pairs, male and female, it is said, living in faithful union for many years, sharing between them the domestic arrangements, which comprise hatching the young and nursing them in their helplessness, carrying them into warm and sunny places, and sheltering them from cold and damp.

Lizards feed chiefly upon insects, and especially flies. All who have watched the actions of the Grey Lizards must have observed that the caudal vertebræ are so extremely fragile that they separate on the slightest touch, the tail remaining in the hand of any one attempting to seize it. These tails sometimes grow again. When an attempt is made to seize a Grey Lizard on the wall it lets itself fall to the ground, and remains there a moment immovable before attempting to run, evidently simulating death.

Grey Lizards are easily tamed, and appear happy in captivity. From their extreme gentleness they soon become familiar with their keepers, and return caress for caress, approaching mouth to mouth, and suck the saliva from between their lips with a grace that few people would allow them to display.

In the Green Lizard, _L. viridis_, the scales of the temple are many-sided and unequal, with a central layer; back granular and oblong, with shelving sides; throat fold distinct. Nothing can be more brilliant than the variegated colouring with which it is ornamented. Its favourite locality is a slightly elevated woody place, where the sun's rays readily penetrate. It is also found in sunny meadows. It feeds upon small insects, and shows no alarm at the presence of Man, but stops to look at him. Snakes, on the contrary, they seem to fear much, but when they cannot avoid them they fight courageously. In length they are about eighteen inches.

Green Lizards are found in Jersey and Guernsey, and other warm countries of Europe, on the African coast of the Mediterranean, and they are not rare in France.

How often have we admired their magnificent colours in the neighbourhood of Montpelier, where they rival the green of the meadows, and glitter in the sun like so many living emeralds!

In the Ocellated Lizard, _L. ocellata_, the upper part of the body is green, variegated, spotted, and reticulated or ocellated with black, having large round blue spots upon the flanks; the underpart of the body is white, frosted with green; in size it is about twenty inches. They are found at Fontainebleau, in the south of France, and in Spain. They establish themselves in hard sand, often between two beds of calcareous rock, upon some steep declivity, more or less directly exposed to the south; they are also found between the roots of old stems, either in hedgerows or vineyards. They feed almost exclusively on insects; but are said to attack Mice, Shrews, Frogs, and even Snakes, and to destroy the eggs of the Partridge. They have sometimes been tamed by feeding them on milk.

[In the genus _Ophiops_, two species of which inhabit Asia Minor, and one of them the shores of the Mediterranean, the eyelid is rudimentary and the eye exposed, whence the name, signifying "snake eye." So far as known, the habits of the various Lizards which constitute the family of _Lacertidæ_ are much the same.

The family of _Teidæ_ is peculiar to the New World, and some of the species attain to the length of several feet. In these Lizards the head is pyramidal, and is covered with regular many-sided shields; supra-orbital plate horny; the teeth solid and well rooted; tongue elongate, flat, free (rarely slightly sheathed at its base); the scales of the back are regular and keeled, and of a rhombic shape; sides flat, and covered with small granular scales; the throat scaly, with a double collar, rarely indistinct.

In some the throat has two cross-folds, with large six-sided scales within; and of these some have the ventral shields small, long, and smooth, while others have them much broader. The former are known as the Teguexins (_Teius_ and _Callopistes_), and the latter as the Ameivas (_Ameiva_, and three other genera). One species of Teguexin, _Teius teguexin_, may commonly be seen alive in the London Zoological Gardens. This is a large and powerful Lizard, exceeding five feet in length when full grown, and extremely active. It feeds on small living animals of any kind, and will even devour poultry, and especially their eggs, for which latter it manifests an especial liking, as observed in captivity. Sometimes it has been known to prey on other and kindred Lizards, as the Ameivas. The teeth of this species are strong, and the reptile can bite with great force. It is a bold and determined combatant when attacked, and if it succeeds in seizing its foe, retains its hold with pertinacity. Its flesh is eaten by some people, who consider it excellent. Together with a second species, _T. nigropunctatus_, it inhabits Brazil, and the two species of _Callopistes_ are also South American, one at least of them occurring in Chili. The species of this family, although strong and agile, never ascend trees, but range at will the hot sandy plains or the dense and damp underwood on the margins of lakes and rivers, into which they plunge when alarmed, and remain below the surface until the danger has passed away, their capacious lungs and imperfect circulation permitting them to endure a very long immersion without inconvenience.

The Ameivas have a long whip-like tail, and peculiarly elongated toes on their hind feet. The species of _Ameiva_ and _Cnemidophorus_ are numerous, and the genera _Dicrodon_ and _Acrantus_ are founded each of them upon a single species. In general these are Lizards which correspond with the ordinary _Lacertidæ_ of the Old World. One species only, _Cnemidophorus sex-lineatus_, inhabits the Southern States of North America; there are at least four others in Mexico, and the rest belong to South America and the Antilles. "The _Ameiva dorsalis_," writes Mr. Gosse, "is one of the most common of the reptiles of Jamaica, and is as beautiful as abundant. Its colours are striking, but not showy, and its countenance has a very meek expression. All its motions are elegant and sprightly; when it is proceeding deliberately, its body is thrown into latent curves the most graceful imaginable; but when alarmed its swiftness is so excessive that it appears as if it literally _flew_ over the ground, and the observer can scarcely persuade himself that it is not a bird. It is very timid, and though its toes are not formed as in the Geckos and Anoles, for holding on against gravity, I have seen a large Ameiva run with facility on the side of a dry wall, along the perpendicular surfaces of the large stones."

A second series occurs in those _Teidæ_ which have a collar of large shields on the throat. As many as five genera of them have been established, each upon a single species, and all are from intertropical America. In _Crocodilurus lacertinus_ the two rows of crests along the tail recall to mind the Crocodiles, whence the name bestowed. Others have been styled Dragons, as the Great Dragon, _Ada guianensis_, and the Smaller Dragon, _Custa bicarinata_. All bear a certain amount of superficial resemblance to the Crocodiles, and the Great Dragon grows to six feet in length, and is found in many parts of South America. This large reptile runs up the trunks of trees with facility, is quick when on the ground, and it also swims, though not particularly well. It preys upon such small animals as it can manage to seize, and chiefly frequents the inundated savannahs and marshy localities, where it is seen basking in the sunshine; but there is considerable difficulty in taking this Lizard, as it makes generally for its burrow in some raised spot, and bites desperately in self-defence. Its flesh is eaten, and is considered a delicacy. Its eggs, also, are considerably esteemed at Cayenne and other places, and each female lays some dozens of them.

The family of _Helodermidæ_ is founded on a very remarkable Lizard from Mexico, the _H. horridum_, which is of the same size as the Great Dragon, and in some respects approximates the following Old World family of _Varanidæ_. Its back and sides are covered with oblong, hexagonal, very convex and shield-like scales, and the belly with oblong, rather convex plates; tail cylindrical, with oblong, convex scales above, and flat, elongate, thin plates beneath. The head is somewhat flattened, and is covered with polygonal, convex shields; the muzzle is rounded; and the teeth are on the inner side of the jaws, incurved, with a groove on the front of their inner side. The bite of this reptile is said to be severe.

The family of _Varanidæ_ inhabit South-eastern Asia and its islands, Africa, and Australia. In this family are comprised the largest of existing Lizards, with the exception of the _Crocodilidæ_. They are very commonly miscalled Iguanas by Europeans and their descendants, in the countries where they are found. These reptiles have a pyramid-shaped head, more or less elongated, and covered with small and scale-like, but not imbricate, shields. Their teeth are acute and compressed. The tongue is elongate, slender, terminating in a long fork, and is retractile into a sheath at its base. Their scales are small, equal on the sides and on the back, and arranged in cross rings; those on the belly and tail are square, in cross bands. Tail long, and generally more or less compressed. The feet are well developed, with five toes on each, which are armed with strong claws. Most of them live near water, and they are excellent swimmers, their long and compressed tail serving as a propeller. Their movements on land are not much less rapid than in the water. Several of the species climb trees, and they are more or less nocturnal in their time of action, though also about by day. They are exclusively carnivorous, feeding on the different water animals, and on the eggs of birds, and likewise on those of other large reptiles; some of them are also destructive to ducklings, and to various Snakes. Dr. Günther remarks that "their external nasal opening leads into a spacious cavity situated in the snout; when the animal dives, it closes the nasal aperture, and retaining a certain quantity of air in that pouch, or rather in the two pouches, it is enabled to remain under water for a prolonged period without the necessity of rising to the surface in order to breathe. It is the same plan of structure as that with which a large northern Seal (_Cystophora borealis_) is provided." In like manner, the air-bag connected with the one developed lung of the Ophidians retains the necessary supply of air during the tedious process of deglutition or swallowing. The nostrils are variously placed, either mid-way between the eye and muzzle, or nearer to one or to the other; and according to this and some other differences, Dr. Gray divides the _Varanidæ_ into as many as seven genera, but Dr. Günther would seem to admit not more than two genera. When the tail of these Lizards is mutilated, the lost portion is never renewed; whereas in the preceding families of the _Zonuridæ_, _Lacertidæ_, and _Teidæ_ a new tail or portion of one soon sprouts forth--but this renewed portion contains no bony vertebræ, and it remains smooth externally; when the fracture is cleft, as sometimes happens, two new tails are put forth. Another family of Lizards in which the tail is thus commonly renewed is that of the Geckos; but never in the _Iguanidæ_, the _Agamidæ_, and the _Chameleonidæ_, any more than in the _Varanidæ_. The species of this family defend themselves vigorously, when attacked, by lashing forth smart blows with the tail, as do also the Crocodiles and the larger _Iguanidæ_.

In the genus _Varanus_, the nasal apertures form an oblique slit, in, or nearly in, the middle, between the eye and the tip of the snout. The scales are elliptic and small; those on the back and on the sides are not imbricate, each of them being surrounded by a small, circular, granular fold. Tail with a low crest, formed by two or four series of strongly keeled scales. Throat with a transverse fold. One very common in India and Ceylon is the _V. dracæna_, which grows to a length of five feet, the tail being longer than the body. These reptiles live in holes, and in mid-day they steal out of their cells to seek their food, which consists chiefly of the smaller reptiles and of insects. In many parts of India, and in Ceylon, the flesh is much eaten by the natives. The late Dr. Kelaart states that he once tried some excellent soup made from it, which tasted not unlike hare-soup. At Trincomali, he tells us, they are hunted down by Dogs, and sold in the market for sixpence each. This species climbs walls, and holds on so firmly with its strong claws, wherever these can be inserted, that it is actually used by house-breakers in India to help in raising themselves up a wall or building, the man grasping the tail, while the reptile affords a lift by endeavouring to escape from him upwards. It lays twenty or thirty eggs, which in texture and appearance resemble those of many Snakes, being similarly agglutinated together by a viscid mucus. Sir J. E. Tennent remarks that "one of the earliest, if not the first, remarkable animal to startle a stranger on arriving in Ceylon, whilst wending his way from Point de Galle to Colombo, is this large Lizard, which may be seen at noonday searching for Ants and other insects in the midst of the highway and along the fences. When disturbed, but by no means alarmed, by the approach of Man, it moves off to a safe distance; and the intrusion being at an end, it returns again to the occupation in which it had been interrupted. It lives in any convenient hollow, such as a hole in the ground, or the deserted nests of the Termites; and some small ones, which frequented my garden at Colombo, made their retreat in the heart of a decayed tree."

Of another species, _V. flavescens_, which inhabits Lower Bengal, and to the eastward in Burmah, &c., Mr. Theobald remarks that "large specimens are not often procurable by Europeans, as they are much sought after by both Burmese and Karéns as choice articles of food. They are chiefly hunted with Dogs, whose scent enables them to discover the Varans in the hollow trees in which they habitually shelter themselves. A Burman, though ordinarily a lazy man, will think nothing of cutting down and breaking up a large tree in which one of these creatures has sought refuge. The _Varanidæ_ deposit their eggs in the ground, usually selecting a deserted White-ant's nest. The eggs are cylindrical, with tapering ends, of a dirty white colour and leathery texture (those of _V. dracæna_ are two inches long), and, being esteemed an uncommon luxury by the Burmese, sell dearer than fowls' eggs. They are oily and feculent-looking, though devoid of any nauseous odour, and some Europeans eat them with pleasure."

A well-known African species, the _V._ or _Psammosaurus scincus_, extends (without the slightest difference) to the extreme desert region of the north-west of India, and more habitually frequents dry localities than others. In this species the nasal apertures are placed very near the eyes.

In the genus _Hydrosaurus_, the nostrils are more or less rounded, and are situate near the extremity of the snout. These animals are more decidedly aquatic than the preceding, and some of the species grow to seven or even eight feet in length. Such is the _H. giganteus_ of Australia, where three, if not four, species inhabit. In all south-eastern Asia and its islands, its range extending to Lower Bengal but not to India proper, although found in Ceylon, the _H. salvator_ is a common species, which, according to the late Dr. Cantor, is "very numerous in hilly and marshy localities of the Malayan peninsula. It is commonly, during the day, observed in the branches of trees overhanging rivers, preying upon birds and their eggs and smaller Lizards, and when disturbed it throws itself from a considerable height into the water; it will courageously defend itself with teeth and claws, and by blows with its tail."

We have now to treat of the

PACHYGLOSSA,

which are those Lizards which have the tongue short, thick, attached to the gullet, and not exsertile. These fall under two very distinct tribes--the _Strobilosaura_ and _Nyctisaura_ of Dr. Gray, or the tribe of the Iguanas and their kindred, and that of the Geckos and their kindred. The tribe of

STROBILOSAURA

Have the scales of the back and sides imbricate, generally rhombic, and those of the lower parts imbricate and of small size. Tail with more or less distinct whorls of scales. The eyes diurnal, with round pupil, and valvular lids. Feet with toes of very unequal length. Many of these reptiles have a row of spines or spine-like scales along the back and tail, which in some are very long, while others have high dorsal and caudal crests, an expansile gular pouch, or other adornments. Like the Varans among the _Leptoglossa_ (p. 114), these Lizards do not renew the tail, or a portion of it, after mutilation. There are two great families of them--one peculiar to the Old World with Australia, the other to the New World; but as families they do not differ much, and might very well be retained as divisions of the same extensive family.

In the family of _Iguanidæ_, all of which inhabit America or its islands, the teeth are round at the root, dilated and compressed at the tip, and toothed at the edge; they are placed in a simple series on the inner side of the jaws, just below the edge, and are covered on the inner side by the gums; as they fall out they are replaced by others, which grow at the base of their predecessors, and gradually cause the absorption of their roots. Probably not fewer than a hundred and fifty species are now recognised, which are distributed under more than fifty genera. We can only notice a few of the most remarkable of these Lizards, some of the larger of which attain a length of five or six feet, with proportionate bulk of body. As a general rule, the larger species are mainly herbivorous, while the smaller are chiefly insectivorous, though many of the latter also devour fruit. As most of them are remarkable for their rapid changes of colouring, the name of Chameleon is often misapplied to them, in the supposition that the Chameleons are the only Lizards in which that curious phenomenon is observable. In one remarkable species, the _Sphærops anomalus_, inhabiting Brazil, it is stated that the eye nearly resembles that of the true Chameleons, and it is also one of those which are particularly celebrated for its changes of hue.]

The name _Iguana_ was given by Laurenti to a heterogeneous group of Saurians, various forms being included which were first separated by Daudin. The Iguanas, as thus restricted, are characterized by a very large thin dew-lap under the neck, a double row of small palatal teeth, and a crest on the back and tail; the latter long, slender, compressed, and covered with small imbricated and carinated scales. Messrs. Duméril and Bibron describe the genus, thus modified, as principally remarkable for the cutaneous prolongation which constitutes the deep and thin dew-lap, or pouch, the free border of which describes a curved line, and is dentated at the part nearest the chin. The head is moderately long, and has the form of a pyramid with four faces. The neck is slightly compressed, the limbs long, the toes unequal and sometimes denticulate on the edge. The five toes of the posterior feet are graduated; the tail, which is long and slender, is slightly flattened from right to left. The Iguanas live chiefly on trees, but they take readily to the water, swimming with great facility.

There are numerous species, all of which are found in South America and the Antilles. In the Island of Isabella, Sir E. Belcher found swarms of them which he had reason to consider omnivorous, feeding voraciously on birds' eggs and the intestines of birds and insects.

The Common Iguana, _I. tuberculata_, which inhabits a great part of South America, is one of the best known species of this family. These reptiles are easily recognised from the large pouch underneath the neck, and the dentated crest which extends from the head to the extremity of the tail. The tail, feet, and body are covered with small scales. On the upper part, their colour is a more or less decided green, sometimes becoming blue, at others slate-coloured; the lower part is of a yellowish green. The sides present zigzag, roundish, brown scales, edged with yellow; frequently a yellow line is traced obliquely in front of the shoulder, and some individuals are sprinkled with brown; others have the limbs spotted with brown on a black ground. The tail is surrounded with brownish rays alternating with others green and yellow. When full grown it attains the length of four feet, but the more ordinary length of the animals is about thirty inches. They are very gentle creatures, and perfectly harmless, feeding almost exclusively on vegetables. They are hunted in America for their flesh, which is excellent; and they are especially common at Surinam, in the neighbourhood of Cayenne, and in Brazil.

[Of a kindred species, _Metopoceros cornutus_, which also is common in the Antilles, an excellent description has been published by Lieutenant Tyler,[22] which we must endeavour to condense. This reptile attains a length of five, and sometimes even of six feet, the tail being about twice and three quarters the length of the body. When first hatched it measures four inches. The mouth is large, and is armed with two rows of maxillary and two of palatal teeth, which appear simply to be intended to crop leaves and to provide the stomach with vegetable food. Each maxillary tooth is a little double-edged saw, and they are so lapped over each other that the reptile, in closing its mouth upon a leaf, cuts through it completely. The tongue is curiously used by the animal to draw food into the mouth, and to forward it down the gullet, or to repel it at will, and the only use of the palatal teeth appears to be to secure the food while the tongue moves forward to afford fresh assistance in its journey down the throat. The tongue is always covered by a glutinous secretion, which is perceptibly appended to the jaws when the mouth is open. Between the lower jaw and the chest is a pouch, which the animal draws in or extends simultaneously with the compression or swelling out of the body when enraged or excited. The portion of the gular pouch attached to the jaw is inflatable, and food is sometimes retained in it for a considerable period, but the lower part is merely extensible.

[22] "Proceedings of the Zoological Society" for 1850, p. 106.

"Whilst always retaining the same colours, this Iguana has the power of considerably changing its hues; but these changes are gradually performed. The colours become more dull as the period of the change of cuticle approaches--which is not, however, very frequent. Each scale has its own tint, and the colours being thus irregularly blended, an appearance is given, particularly to the younger reptiles, very much like that of worsted-work.

"These Iguanas live principally on trees, and near the windward coast of the island" (of St. Lucia). "They are not much seen, excepting in the months of February, March, and April, when they quit their hiding-places, and repair to the sea-shore or other sandy places to lay their eggs in the sand. The older females lay a great number of eggs. I have known an instance of one in confinement laying five in one day, and thirty-two within the space of ten minutes five days afterwards, making thirty-seven in all. Younger females are much less prolific, according to their size. The eggs are very liable to destruction by Ants, which fact probably accounts for their being usually deposited in sea-sand. They are soft, and without any white, and their shell resembles the most beautiful kid leather used for French gloves, of a very light straw-colour. They are about the size of those of a domestic Pigeon, but rather longer; but they vary in dimensions according to the age and size of the Iguana.

"This Iguana is not averse to water, when not too cold, taking to it only when the sun is shining; in fact, not moving about much at any other time. Its mode of swimming differs from that of other Lizards, inasmuch as it places its four legs close by the side of its body, and swims entirely with its tail. It dives with great facility, and remains sometimes for a considerable time under water. I believe that it never ventures into the sea. The tail is a very valuable limb; for, besides being the sole means of swimming possessed by the animal, it is of great use in climbing trees, although not prehensile; and it is a most important weapon of defence, a blow from it being frequently sufficient to inflict a severe wound. In fact, this reptile is rather formidable when brought to bay in the woods. It is hunted by the natives with Dogs trained for the purpose. The Dog, immediately upon scenting it, gives tongue, and, if on the ground, the Dog seizes it by the back, and either kills it or maims it, which makes its capture easy; if in a tree, the Iguana is either shaken down--a matter ordinarily of no small difficulty--or the branch is cut off. It is almost useless to attempt to find these reptiles without Dogs, as the resemblance of their colour to that of the trees which they inhabit prevents them from being easily seen. Few Dogs but those accustomed to the sport will touch them, as, in addition to the blows which they inflict with the tail, they bite and scratch furiously; and when once they lay hold of anything with their teeth, they can only be made to let go by an inducement to bite some other attractive object being offered to them. They run into holes when chased, if an opportunity offers, and when their eyes are hidden from view, they fancy that their whole body is safely covered. The flesh, particularly of the female, is a great delicacy; it is cooked in various ways, sometimes in a fricassee, with the eggs whole, sometimes roasted or stewed. The eggs have a very glutinous consistence. The flesh is said to disagree with some constitutions.

"Unless when caught young, it is very difficult to induce these reptiles to feed in confinement, and particularly when watched. Their disposition is sulky and savage, and I have known some of them," continues Lieutenant Tyler, "to die in confinement from starvation, rather than feed. This has caused me to try the following plan, which I find very successful, of affording them nourishment:--I hold them by the lower part of the body with one hand, and with the other I irritate them until they open their mouth and attempt to bite, when I insert food; and by annoying them in this way, I have not only made them eat their natural food, but I have killed some of them by forcing them to eat corn and leaves, which appear to have disagreed with them. By some of the natives this Iguana is said to eat Lizards and insects; but I have opened several, and I have never succeeded in finding any but vegetable matter in the stomach."