Zonurus.–The whole head, back, and tail are covered with bony scales, the horny covering of which forms very sharp spikes, especially on the tail. The body is depressed. The ear-opening is large. South Africa, in dry and rocky localities; one species, Z. tropidosternum, in Madagascar.
Z. giganteus s. derbianus, with strong spikes on the occiput, neck, and tail. General colour yellowish brown. Total length about 15 inches.
Chamaesaura of South Africa closely approaches the Anguidae by its snake-shaped body, extremely long tail, and vestigial limbs. In Ch. aenea both pairs of limbs are still present and pentadactyle, but are very small; in Ch. anguina the limbs are reduced to little styliform stumps; and in Ch. macrolepis they are altogether absent. The scales of the body and tail are strongly keeled and imbricating, but are devoid of dermal ossifications. Total length up to 2 feet.
Fig. 135.–Zonurus giganteus. × ¼.
Fam. 5. Anguidae.–Pleurodont lizards with osteoderms, and with the tongue composed of two distinct portions, of which the anterior is thin, emarginate, extensible, and retractile into the posterior thicker portion. The supratemporal fossa is roofed in by dermal bones. The whole body is protected by bony plates underlying the imbricating scales. The teeth vary much in shape, but they are always solid, the new teeth not growing into the base of the old ones, but between them. The limbs are in a very unstable condition, there being in the family a general tendency to reduce and lose the limbs. The shoulder- and pelvic-girdle however remain, although sometimes merely vestigial. The tail is long, very brittle, and easily reproduced. All the Anguidae are strictly terrestrial, and live on animal diet. Some Anguis, at least, are viviparous. The distribution of the seven genera, with some forty species, is very scattered. The majority, chiefly Gerrhonotus, inhabit Central America, a few occur farther north and south–two, Anguis fragilis and Pseudopus pallasi, in Europe, and one in the Himalayas and in Burmah.
Gerrhonotus has a pair of deep longitudinal folds, each of which extends from the region of the neck along the side of the body towards the tail. The four limbs are well developed and pentadactyle. The teeth are conical. Many species, mostly in Central America. G. coeruleus has the widest range, extending from Costa Rica to Vancouver. It is also one of the largest species, reaching a length of more than one foot. The tail is nearly twice as long as the rest of the body. General colour above brown with blackish bars and spots, especially on the more yellowish flanks; under parts whitish with a greenish tinge, often with brown spots arranged in longitudinal rows.
Ophisaurus s. Pseudopus is closely allied to the previous genus, being possessed of the same kind of deep lateral folds; the limbs are, however, reduced to a pair of tiny spikes, half concealed at the sides of the anal cleft. The teeth are conical, and in the adult have somewhat flattened crowns. The body and tail are very long and snake-like, but the head is that of a typical Lizard.
O. apus s. Pseudopus pallasi, the Glass-Snake of the Balkan Peninsula, South Russia, Asia Minor, and Morocco, grows to more than one yard in length, of which about two-thirds belong to the tail. The general colour is brown above, paler below. Young specimens are olive-grey with dark brown cross-bands on the back. O. gracilis inhabits the Eastern Himalayas and Burmah, the others live in North America.
The "Glass-Snake" inhabits bushy localities, where it can hide under the fallen leaves and in the sand; it cannot climb, and avoids the water. Its movements resemble those of a snake, but are far less graceful, owing to the stiff armour in which the whole body is encased. The food consists chiefly of snails, the shells of which are crushed, and of mice, but nothing comes amiss which can be mastered, namely insects, worms, small lizards, young birds, and vipers. The prey, when caught, is rapidly twisted round and round, or shaken until it is giddy or stunned, whereupon the Glass-Snake proceeds to chew it with its powerful jaws, and then to swallow it in pieces. Although it can bite so well, it never does so when caught, but resorts to the much more disagreeable defence of twisting itself around one's hand and arm, and besmearing them with its disgustingly stinking excrements. Those who have observed Glass-snakes praise their tameness, and the intelligent way in which they hunt about in search of their food. They lay eggs under moss and leaves, and the young seem to require many years to grow up.