Page:EB1911 - Volume 16.djvu/848

 worm-shaped creatures. The family is essentially neotropical. Of its several dozen genera only two extend through and beyond Central America: Ameiva into the eastern and western Hot-lands of Mexico, Cnemidophorus (monographed by H. Gadow, Proc. Zool. Soc., 1906, pp. 277-375) through Mexico into the United States, where C. sexlineatus, the “swift,” has spread over most of the Union. Tupinambis teguixin, the “teju” of South America and the West Indies, is the largest member of the family; it reaches a length of a yard, most of which, however, belongs to the strong, whip-like tail. Teguixin is taken from the Aztec teco-ixin, i.e. rock-lizard, the vernacular name of Sceloporus torquatus which is one of the Iguanidae misspelt and misapplied. The tejus frequent forests and plantations and are carnivorous, eating anything they can overpower. They in turn are much hunted for the sake of their delicate flesh. They defend themselves not only with their powerful jaws and sharp claws, but also with lashing strokes of the long tail. They also use this whip for killing snakes which they are said to eat. Their long-oval, hard-shelled eggs are deposited in the ground. They retire into self-dug burrows. Cophias and Scolecosaurus have very much reduced limbs. In the genus Tejus the teeth of the adult become molar-like; and in Dracaena they are transformed into large, oval crushers, indicating strictly herbivorous habits, while most members of the family live upon animal food.

Family 10. Amphisbaenidae.—The body is covered with soft skin, forming numerous rings with mere vestiges of scales. Worm-shaped, without limbs, except Chirotes which has short, clawed fore-limbs. Eyes and ears concealed. Tongue slightly elongated, covered with scale-like papillae and bifurcating. Tail extremely short. Acrodont or pleurodont. America, Mediterranean countries, and Africa with the exception of Madagascar.

Chirotes canaliculatus, and two other species; Pacific side of Mexico and Lower California. With five, four or three claws on the stout little digging fore-limbs. These pink, worm-like creatures live in sandy, moist localities, burrowing little tunnels and never appearing on the surface.  (q.v.). Rhinëura of Florida, and also known from the Oligocene of South Dakota; Lepidosternum of South America; and Anops in America and Africa; Blanus cinereus, Mediterranean countries. Trogonophis, Pachycalamus and Agamodon of Africa are all acrodont; the other genera are pleurodont. In all about a dozen genera, with some 60, mostly tropical species.

Family 11. Scincidae.—Pleurodont. Tongue scaly, feebly nicked in front. Osteoderms on the head and body. Limbs often reduced. Cosmopolitan. The temporal region is covered over, as in the Lacertidae and Anguidae, with strongly developed dermal ossifications. Similar osteoderms underlie the scales of the body and tail. Femoral pores are absent.

All the skinks seem to be viviparous, and they prefer dry, sandy ground, in which they burrow and move quickly about in search of their animal food. This partly subterranean life is correlated with the frequent reduction of the limbs which, in closely allied forms, show every stage from fully developed, five-clawed limbs to complete absence. Some have functional fore-limbs but mere vestiges of hind-limbs; in others this condition is reversed. In some deserticolous kinds e.g. Ablepharus, the lower eyelid is transformed into a transparent cover which is fused with the rim of the reduced upper lid. The same applies to the limbless little Ophiopsiseps nasutus of Australia. This large family contains about 400 species, with numerous genera; the greatest diversity in numbers and forms occurs in the tropical parts of the Old World, especially in the Australian region, inclusive of many of the Pacific islands. New Zealand has at least 6 species of Lygosoma. America, notably South America, has comparatively very few skinks.

The skink, which has given the name to the whole family, is a small lizard (Scincus officinalis) of 6 or 8 in. in length, common in arid districts of North Africa and Syria. A peculiarly wedge-shaped snout, and toes provided with strong fringes, enable this animal to burrow rapidly in and under the sand of the desert. In former times large quantities of it were imported in a dry state into Europe for officinal purposes, the drug having the reputation of being efficacious in diseases of the skin and lungs; and even now it may be found in apothecaries’ shops in the south of Europe, country people regarding it as a powerful aphrodisiac for cattle.

Mabouia, with many species, in the whole of Africa, southern Asia and in tropical America. M. (Euprepes) vittata, the “poisson de sable” of Algeria, is semi-aquatic. Chalcides s. Seps, of the Mediterranean countries and south-western Asia, has a transparent disk on the lower eyelid which is movable; limbs very short or reduced to mere vestiges. Lygosoma circumtropical; Eumeces, also with many small species, in America, Africa and Asia. Cyclodus s. Tiliqua of Australia, Tasmania and Malay Islands, has stout lateral teeth with rounded-off crowns; C. gigas of the Moluccas and of New Guinea is the largest member of the family, reaching a length of nearly 2 ft.; the limbs are well developed, as in Trachysaurus rugosus of Australia, which is easily recognized by the large and rough scales and the short, broad, stump-like tail.

Family 12. Anelytropidae.—An artificial assembly of a few degraded Scincoids. The worm-shaped body is devoid of osteoderms. The tongue is short, covered with imbricating papillae and slightly nicked anteriorly. Teeth pleurodont. Anelytropsis papillosus, of which only three specimens are known, from the humus of forests in the state of Vera Cruz. Eyes concealed. Typhlosaurus and Feylinia in tropical Africa and Madagascar.

Family 13. Dibamidae.—Dibamus novae-Guineae of New Guinea, the Moluccas, Celebes and the Nicobar Islands. Tongue arrow-shaped, covered with curved papillae. The vermiform body is covered with cycloid imbricating scales, devoid of osteoderms. Limbs and even their arches are absent, excepting a pair of flaps which represent the hind-limbs in the males.

Family 14. Gerrhosauridae.—Pleurodont. Tongue long, with papillae, like that of the Lacertidae but only feebly nicked anteriorly. Osteoderms on the head and body, roofing over the temporal region. Femoral pores present, also mostly a lateral fold. Limbs sometimes reduced to small stumps. Tail long and brittle. The few genera and species of this family are restricted to Africa, south of the Sahara and Madagascar.

Gerrhosaurus, with lateral fold and complete limbs; Tetradactylus also with a fold, but with very variable limbs; Condylosaurus; all in Africa. Zonosaurus and Tracheloptychus in Madagascar.

Family 15. Lacertidae.—Pleurodont. Tongue long and bifid, with papillae or folds, with osteoderms on the head but not on the body. Limbs always well developed. Palaearctic and palaeotropical with the exception of Madagascar; not in the Australian region.

The Lacertidae or true lizards comprise about 20 genera, with some 100 species, most abundant in Africa; their northern limit coincides fairly with that of the permanently frozen subsoil. They all are terrestrial and zoophagous. The long, pointed tail is brittle.

—Heads of British Lizards. a, Lacerta vivipara; b, L. agilis; c, L. viridis.

Most of the European lizards with four well developed limbs belong to the genus Lacerta. Only three species occur in Great Britain (see fig. 2). The common lizard (Lacerta vivipara) frequents heaths and banks in England and Scotland, and is locally met with also in Ireland; it is viviparous. Much scarcer is the second species, the sand-lizard (Lacerta agilis), which is confined to some localities in the south of England, the New Forest and its vicinity; it does not appear to attain on English soil the same size as on the continent of Europe where it abounds, growing sometimes to a length of 9 in. Singularly, a snake (Coronella laevis), also common on the continent, and feeding principally on this lizard, has followed it across the British Channel, apparently existing in those localities only in which the sand-lizard has settled. This lizard is oviparous. The males differ by their brighter green ground colour from the females, which are brown, spotted with black. The third British species, the green lizard (Lacerta viridis), does not occur in England proper; it has found a congenial home in the island of Guernsey, but is there much less developed as regards size and beauty than on the continent. This species is larger than the two preceding; it is green, with minute blackish spots. In Germany and France one other species only (Lacerta muralis) appears; but in the south of Europe the species of Lacerta are much more numerous, the largest and finest, being L. ocellata, which grows to a length of 18 or 20 in., and is brilliantly green, ornamented with blue eye-like spots on the sides. Even the small island-rocks of the Mediterranean, sometimes only a few hundred yards in diameter, are occupied by peculiar races of lizards, which have attracted much attention from the fact that they have assumed under such isolated conditions a more or less dark, almost black, coloration. L. muralis, with its numerous varieties, has been monographed by G. A. Boulenger, ''Trans. Zool. Soc.'' xvii. (1905), pp. 351-422, pl. 22-29.

Other genera are Psammodromus and Acanthodactylus in south-western Europe and northern Africa. Cabrita in India, with transparent lower eyelids. Ophiops, likewise with transparent but united lids, from North Africa to India.

Family 16. Varanidae.—Pleurodont. Tongue very long, smooth and bifid. Osteoderms absent. Limbs always well developed. Old World.

This family contains only one genus, Varanus, with nearly 30 species, in Africa, Arabia and southern Asia, and Australia, but not in Madagascar. The generic term is derived from the Arabic Ouaran, which means lizard. Owing to a ridiculous muddle, this Arabic word has been taken to mean “warning” lizard, hence the Latin Monitor, one of the many synonyms of this genus, now often used as the