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.
| Fig. 2.—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 vernacular. Many of the “monitors” are semi-aquatic, e.g. V. niloticus, and these have a laterally compressed tail; others inhabit dry sandy districts, e.g. V. scincus, the ouaran el ard of North Africa; others prefer wooded localities. V. salvator is the largest species, reaching a length of 7 ft.; it ranges from Nepal and southern China to Cape York; a smaller species, common in New Guinea and Australia, is V. gouldi. They all are predaceous, powerful creatures, with a partiality for eggs. Their own eggs are laid in hollow trees, or buried in the sand. The young are prettily spotted with white and black ocelli, but the coloration of the adult is mostly very plain.