Maxillary, palatine, and pterygoid bones movable; transverse bone present; pterygoid extending to quadrate or mandible; supratemporal present, attached scale-like to cranium, suspending quadrate; prefrontal in contact with nasal; a coronoid element in the lower jaw. Teeth in both jaws. Vestiges of pelvis and hind limbs, usually terminating, at least in males, in a claw-like horny spur on each side of the vent.

This family contains, besides the gigantic Boas and Pythons, several small more or less burrowing forms, among which the genus Eryx, its only European representative, belonging to the subfamily BoinÆ, characterized by the absence of a supratemporal bone and of premaxillary teeth. This subfamily, the largest members of which inhabit tropical America, is distributed over the hotter parts of America, Asia west of the Bay of Bengal, Madagascar, the Mascarene Islands, Africa north of the equator, Papuasia, and some islands of the South Pacific. The habitat of the European species is confined to the eastern and southern countries of the Mediterranean district.

This very varied family, including terrestrial, arboreal, aquatic, and burrowing forms, is a comparatively small one as regards the number of species, viz., about sixty, of which one-third pertain to the PythoninÆ, which inhabit tropical and South Africa, Southern Asia, Papuasia, Australia, and Mexico.

Anterior maxillary and mandibular teeth longer than the posterior. Head small, not distinct from neck, covered with small scales; a large rostral shield. Eye very small, with vertical pupil. Body cylindrical; scales small; ventral shields narrow. Tail very short; subcaudal shields mostly single.

The range of this genus, embracing eight species, extends from South-Eastern Europe and Africa north of the equator to Central Asia and India.

Form.—Stout. Head small, not distinct from neck; snout projecting beyond the mouth; eye directed upwards and outwards; a feeble mental groove. Tail, ending very obtusely, one-tenth to one-sixteenth of the total length. Anal spurs more or less developed, often absent in the female.

Head-Shields.—Rostral very large and broad, with angular horizontal edge, followed by a pair of internasals and a second row of two or three small shields, the rest of the upper surface of the head covered with scale-like shields, 5 to 8 from eye to eye across the vertex, 7 to 11 round the eye; 9 to 12 upper labials, second or third deepest, separated from the eye by one or two series of scales. Nostril between the internasal and two nasals, the anterior of which sometimes fuses with the former. Two or three series of scales between the nasals and the eye.

Coloration.—Pale greyish, reddish, or yellowish-brown above, with brown, purplish-brown, or blackish markings, which may be very irregular or form a single or alternating series of large blotches or cross-bands on the back; the sides with smaller spots; these markings may be confluent and so large as to reduce the ground colour to small yellowish spots; one, two, or three short, dark stripes often present on the nape; a dark streak from the eye to the angle of the mouth; sometimes a dark curved band from eye to eye across the upper surface of the snout. Lower parts yellowish-white, uniform or with small blackish spots.

Size.—21/4 feet is the greatest length which this snake is known to attain.

Distribution.—Originally described from Lower Egypt, and extending westwards to Algeria, this Eryx has been found in Greece, in Corfu, in the Cyclades, in Turkey, and in Roumania. It occurs also in Asia Minor, in Transcaucasia, in Transcaspia, in Northern Persia, and in Syria. It has been found at an altitude of 5,000 feet in Persia, to the west of Lake Urmia. A closely allied form (E. miliaris, Pallas), which has been confounded with this species, extends from Transcaspia to Turkestan and Afghanistan.

The reported occurrence of this snake in Bulgaria is based on a specimen labelled “Bulgaria (?)” in the Sofia University Museum. The species is omitted from Kovatscheff’s latest list of Bulgarian Reptiles.

Habits.—This diminutive Boid is a burrower in arid, sandy districts, appearing only early in the morning or towards dusk; it is as a rule more crepuscular than nocturnal. Notwithstanding its rather heavy form, it is capable of very quick movements, darting like an arrow upon its prey, which consists chiefly of small mammals and lizards. A constrictor, like all the members of the family to which it pertains, it crushes its prey before swallowing it. If given several mice at a time, it will catch and kill them all in succession before proceeding to feed. Specimens recently discovered in the Danube Valley in Roumania were found to live in the sand at the bottom of small limestone caves, going about at night and feeding principally on slugs. Unlike other snakes, it is said to lap dewdrops with its tongue. It is a gentle snake, seldom attempting to bite.

Egyptian jugglers are in the habit of implanting the claw of a bird or small mammal in the skin of the head of this snake, above each eye, in order to give it a more formidable appearance.

Reproduction.—Like the other species of Eryx, this snake is ovoviviparous, but, beyond this fact, nothing appears to have been observed concerning the breeding habits, although many examples have been kept in captivity.