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. GENUS ERYX, DAUDIN 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. 2. ERYX JACULUS, Linnæus The Javelin Sand-Boa _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. [Illustration: FIG. 15 (after Sordelli)] _Scales._--Smooth, feebly keeled on the posterior part of the body and on the tail, in 40 to 51 rows. Ventrals narrow, occupying about one-third of the ventral surface, 163 to 200; anal small, entire; subcaudals all or greater part single, 15 to 29.