Lizard, the common name of several families of saurian reptiles, but properly restricted to the family lacertini, or the autosaurian group of Dumeril and Bibron. Many iguanas, geckos, monitors, and skinks have been called lizards; the green anolis and the blue-tailed skink are familiar examples in this country. The lizard may be defined as a scaly reptile, with elongated body; four feet armed with four or five unequal and free toes; long conical tail clothed with scales disposed in parallel rings; head protected by horny plates, flattened and narrow in front; the tympanum membranous and distinct, and the eyes generally with three movable lids; the mouth wide, surrounded by large scales above and below; teeth of unequal size and shape, inserted on the internal border of a common groove in the projecting portion of the maxillary bones, and frequently also on the palate; tongue slender, free, fleshy, more or less extensible and forked at the point; the scales without prominent crests, those of the abdomen large; the neck without dewlap, but often with one or two transverse folds covered with tubercles or broad scales which form a kind of collar separated from those of the abdomen by smaller ones; the false ribs do not make a complete circle.

The family of lizards may be divided into two subfamilies, according to the structure and mode of insertion of the teeth; the first, according to Du-meril and Bibron, is the pleodont, and the other the coelodont; in the pleodonts the teeth are solid, and firmly fixed by their edges and external surface to the jaws in a hollow of the interior border; in the coelodonts the teeth have an interior canal, and are slightly attached to the jaws. The pleodonts are further subdivided into the flat-tailed and conical-tailed groups, and the coelodonts into the smooth-fingered and the serrated-fingered groups, distinguished also by their habits. The first group pass most of their lives in the water or inundated places; the second avoid wet situations; the third frequent woods and gardens, and the last dry and desert localities. Nineteen genera are described, established on the form of the tongue and teeth, the situation of the nostrils, the presence or absence of femoral pores, the form and distribution of the abdominal plates, and the characters of the tympanum and collar; for details the reader is referred to the writers above cited.

This family is one of the best known among reptiles, as its members are for the most part easily obtained in Europe and America; they vary in length from a few inches to 3 or 4 ft.; the colors are often pleasing, but the tints vary much according to sex, age, and season. Lizards are very rapid in their movements for short distances, both on land and in the water; the loss of the tail is frequent from various accidents, but it is very soon replaced; from their scaly covering the sense of touch must be dull; so also are smell and hearing; the moist and movable tongue indicates greater development of the sense of taste; vision is generally very good. Various shades of green, yellow, gray, black, white, blue, and red are found in the family; the epidermis is ordinarily renewed several times a year, being detached in fragments or plates, and at each moult the colors appear brighter, especially in the males. Lizards drink by lapping; their favorite food consists of insects, terrestrial mollusks, worms, eggs, and for the larger species small birds, reptiles, and mammals; the muscles of the jaws are powerful, and their bite is severe and long continued; most genera are oviparous, but one genus brings forth the young alive; the flesh of some of the larger species is considered a delicacy in South America. All the pleodonts belong to the new world, and all the coelodonts to the continents of Europe, Asia, and Africa; the six-lined ameiva only is found in North America. The flat-tailed pleodonts or crocodilurians are among the largest of the family; they may be recognized by the crocodilian form of the tail, surmounted by two serrated crests, a powerful swimming organ; though the feet are not palmated, these reptiles pass most of their lives in the water, the rivers, lakes, and swamps of tropical South America; some attain a length of 2 1/2 ft., of which the tail is about two thirds.

Of the conical-tailed pleodonts the best known genus is ameiva (Cuv.), numerous in species, not partial to moist places, living on worms, insects, mollusks, and even on vegetable food. The six-lined ameiva (A. sex-lineata, Holbr.) is common in the southern states; the usual length is about 10 in., of which the tail is two thirds; the color is dark brown above, marked with six yellow longitudinal lines, and silvery white below. It is very active, frequenting dry and sandy places; it is very timid, and feeds on insects, which it generally procures toward the close of the day. The great American safeguard or teguexin, the largest of the ameiva lizards, grows to a length of more than 4 ft.; it is voracious, and preys upon mice, frogs, and animals of similar size, and its white flesh is esteemed by the Brazilians; it is a swift runner, and when pursued will bite, and strike severely with its tail; it is the tejus monitor (Merr.), and frequents the woods and dry places of tropical South America. - The cocelodonts, or hollow-toothed lizards of the old world, are all terrestrial m their habits; the smooth-fingered group are excellent climbers on trees and walls, of mild disposition, and generally looked upon as friends of man.

This includes the typical genus lacerta (Cuv.), or the lizards properly so called; they have distinct eyelids, femoral pores on the inside of the thighs, and a collar of scales larger than the rest under the throat; the form is generally slender and graceful, and the motions very quick. The European sand lizard (L. stir-pium, Daud.; L. agilis, Linn.) has the back reddish brown, sometimes with blackish spots, the sides green with brown spots, and the lower parts chiefly white; it is about 8 in. long, and of rather stout form; it is found in Europe (except in the northern parts), near the Caspian sea, and in Asia, in level and hilly districts, in which it digs a hole at the foot of a bush or tree; it passes the winter in a dormant state, and feeds in the warm season on insects and larvae; the female lays about a dozen cylindrical eggs. The viviparous lizard (L. vivipara, Jacquin; genus zootoca, Wagler) is about 7 1/2 in. long, of which the tail measures two thirds; the back is olive or reddish brown, with a black band on each side bordered with white above and below, and a black dorsal streak along the spine; the under parts are orange yellow with black spots. The tail does not diminish in thickness until about its middle.

It is found most frequently in mountainous regions of Europe, but occasionally in dark and damp woods; it is timid, very active, and feeds principally on dipterous insects. Toward the month of June the female lays five to seven eggs, from which the young come forth in a few minutes perfectly developed, and sometimes, it is said, the eggs are entirely hatched within the oviducts. The green lizard (L. viridis, Daud.) attains a length of about 18 in., of which the tail is a foot; the color above is either uniformly green, or brown spotted with green, or the latter spotted with yellow, and the under parts yellow; there is considerable variation, and some specimens are marked with white and black streaks. It is generally distributed over Europe (except in the northern parts), northern Africa, and western Asia. The other group of coelodonts have the fingers with lateral serrations or inferior ridges, by means of which they can run rapidly over the arid sand in which they live.

Green Lizard (Lacerta viridis).

Green Lizard (Lacerta viridis).