Page:EB1911 - Volume 16.djvu/847

 leaves, the latter is semi-marine, diving for the algae which grow below tide-marks. For Basiliscus see ; is dealt with under its own heading; allied is Metopoceros cornutus of Hayti. Polychrus, the “chameleon,” and Liolaemus are South American; Ctenosaura of Central America and Mexico resembles the agamoid Uromastix. Corythophanes and Laemanctus, with only a few species, are rare inhabitants of the tropical forests of Central America and Mexico. Sauromalus, Crotaphytus, Callisaurus, Holbrookia, Uma, Uta are typical Sonoran genera, some ranging from Oregon through Mexico. Allied is Sceloporus, with about 34 species, the most characteristic genus of Mexican lizards; only 4 species live in the United States, and only 3 or 4 are found south of the Isthmus of Tehuantepec and are restricted to Central America. The majority are humivagous, while others are truly arboreal, e.g. S. microlepidotus, a species which, moreover, has the greatest possible altitudinal range, from the hot country of southern Oaxaca to the upper tree-line of Citlaltepetl, about 13,500 ft. elevation; many species are viviparous. Phrynosoma, with about a dozen species, the “horned toads” of California to Texas, and through Mexico. Some of these comical-looking little creatures are viviparous, others deposit their eggs in the ground. They are well concealed by the colour of their upper parts, which in most cases agrees with the prevailing tone of their surroundings, mostly arid, stony or sandy localities; the large spikes on the head protect them from being swallowed by snakes. The enlarged spiny scales scattered over the back look as if it were sprinkled with the dried husks of seeds. They are entirely insectivorous, bask on the broiling hot sand and then can run fast enough; otherwise they are sluggish, dig themselves into the sand by a peculiar shuffling motion of the fringed edges of their flattened bodies, and when surprised they feign death. The statement, persistently repeated (O. P. Hay, Proc. U.S. Nat. Mus. xv., 1892, pp. 375-378), that some, e.g. P. blainvillei of California, have the power of squirting a blood-red fluid from the corner of the eye, still requires renewed investigation.

The smallest lizards of this family belong to the genus Anolis, extremely numerous as regards species (more than 100) and individuals on bushes and trees of tropical America, and especially of the West Indies. They offer many points of analogy to the humming birds in their distribution, colours and even disposition. Hundreds may be seen on a bright day, disporting themselves on trees and fences, and entering houses. Like the iguanas, they (at least the males) are provided with a large, expansible dewlap at the throat, which is brilliantly coloured, and which they display on the slightest provocation. This appendage is merely a fold of the skin, ornamental and sexual; it has no cavity in its interior, and has no communication with the mouth or with the respiratory organs; it is supported by the posterior horns of the hyoid bone, and can be erected and spread at the will of the animal. The presence of such dewlaps in lizards is always a sign of an excitable temper. Many, e.g. A. carolinensis, the “chameleon,” can change colour to an extraordinary degree. They are much fed upon by birds and snakes, and have a fragile tail, easily reproduced. They bring forth only one large egg at a time, but probably breed several times during the season.

Family 3. Xenosauridae.—Pleurodont; solid teeth; anterior part of tongue slightly emarginate and retractile, and covered with flat papillae; no osteoderms. Mexico.

The only representative of this family is Xenosaurus grandis, recorded from the mountains of Orizaba, Cordoba and Oaxaca. The four-footed creature is less than 1 ft. in length; the body is depressed, covered above with minute granules and tubercles; a distinct fold of skin extends from the axilla to the groin, reminding of the similar fold of some Anguidae, to which this singular genus seems to be allied.

Family 4. Anguidae.—Pleurodont; teeth solid, sometimes (Ophiosaurus) grooved; anterior part of tongue emarginate and retractile into the posterior portion; osteoderms on the body, and especially on the head where they are roofing over the temporal fossa; entirely zoophagous and ovo-viviparous. America, Europe and India.

Gerrhonotus, 8 species, in mountainous countries, from British Columbia to Costa Rica; like Diploglossus s. Celestus of Mexico, the Antilles and Central America, with well-developed limbs, but with a lateral fold. Anguis fragilis and two species of Ophiosaurus are the only members of this family which are not American, and even the third species of Ophiosaurus, O. ventralis, lives in the United States. Ophiosaurus s. Pseudopus, the glass-snake, from Morocco and the Balkan peninsula to Burma and Fokien; also in the U.S.A., with the limbs reduced to a pair of tiny spikes near the vent, and a lateral fold along the snake-like body. Anguis, with its sole species fragilis, the slow-worm or blind-worm, is devoid of a lateral fold, and the limbs are entirely absent. Europe, Algeria and western Asia.

Family 5. Helodermatidae, with Heloderma of Arizona and Mexico, and Lanthanotus of Borneo.—The teeth of Heloderma are recurved, with slightly swollen bases, loosely attached to the inner edge of the jaws; each tooth is grooved, and those of the lower jaw are in close vicinity of the series of labial glands which secrete a poison; the only instance among lizards. Limbs well developed. Tongue resembling that of the Anguidae. The skin of the upper surface is granular, with many irregular bony tubercles which give it an ugly warty look. H. horridum in Mexico, and H. suspectum, the gila monster, in the hot and sandy lowlands of the Gila basin. The animal, which reaches a length of more than 2 ft., is blackish-brown and yellow or orange, and on the thick tail these “warning colours” are arranged in alternate rings. Small animals are probably paralyzed or killed by the bite, the poison being effective enough to produce severe symptoms even in man. The Zapotecs, who call the creature Talachini, and other tribes of Mexico have endowed it with fabulous properties and fear it more than the most poisonous snakes. Lanthanotus corneensis, of which only a few specimens are known, is apparently closely allied to Heloderma, although the teeth are not grooved, osteoderms are absent and probably also the poison glands.

Family 6. Aniellidae.—One genus, Aniella, with a few worm- or snake-shaped species in California, which seem to be degraded forms of Anguidae. The eyes and ears are concealed, the limbs are entirely absent, body and tail covered with soft, imbricating scales. The tongue is villose, smooth, bifid anteriorly. The few teeth are recurved, with swollen bases. The skull is much reduced. Total length of A. pulchra up to 8 in.

Family 7. Zonuridae.—Pleurodont; tongue short, villose, scarcely protractile, feebly nicked at the tip. With osteoderms at least upon the skull, where they roof in the temporal region. Africa and Madagascar.

Only 4 genera, with about 15 species. Zonurus of South Africa and Madagascar has the whole head, neck, back and tail covered with strong bony scales, the horny covering of which forms sharp spikes, especially on the tail. They defend themselves by jerking head and tail sidewards. Z. giganteus reaches 15 in. in length, and is, like the other members of the family, zoophagous. The other genera live in southern and in tropical Africa: Pseudocordylus, Platysaurus and Chamaesaura; the latter closely approaches the Anguidae by its snake-shaped body, very long tail and much reduced limbs, which in C. macrolepis are altogether absent.

Family 8. Xantusiidae.—Pleurodont; tongue very short and scaly; no osteoderms; supratemporal fossa roofed over by the cranial bones; eyes devoid of movable lids; tympanum exposed; femoral pores present; limbs and tail well developed. American.

Xantusia (so named after Xantus, a Hungarian collector), e.g. X. vigilis and a few other species from the desert tracts of Nevada and California to Lower California. Lepidophyma flavomaculatum, Central America; and Cricosaura typica in Cuba.

Family 9. Tejidae.—Teeth solid, almost acrodont; tongue long and narrow, deeply bifid, beset with papillae; no osteoderms; scales of the back very small or quite granular; limbs sometimes reduced. America.

This large, typically American family comprises more than 100 species which have been arranged in many genera. Some are entirely arboreal, dwellers in forests, while others, like Cnemidophorus and Ameiva, are strictly terrestrial, with great running powers; a few dwell below the surface and are transformed into almost limbless