This species may be divided into several geographical forms. The typical form will be described first.
Form.—Short and heavy. Snout pointed, produced into an erect, horn-like dermal appendage covered with scales; canthus rostralis strong, sometimes slightly raised, loreal region slanting more or less towards the lip. Vertical diameter of the eye less than its distance from the mouth in the adult. Length of tail six to nine and a half times in the total length in males, eight to eleven times in females.
Fig. 38 (after Sordelli)
Head-Shields.—Rostral usually broader than deep. Naso-rostral (rarely divided into two) usually reaching the canthus rostralis, and extending considerably higher up than the upper border of the rostral. Rostral appendage covered with ten to seventeen scales, arranged in three (rarely two or four) transverse series between the rostral shield and the apex. Upper surface of head covered with small smooth or faintly keeled, subimbricate scales, among which a feebly enlarged frontal shield or a frontal and a pair of parietals are rarely distinguishable; when present, the frontal is separated from the supraocular by two series of scales; on the vertex five to eight series of scales separate the supraoculars. Two (rarely three) canthal scales, the second separated from the supraocular by the upper preocular. Supraocular with very convex outer border, usually not extending posteriorly beyond the vertical of the eye. Ten to thirteen scales round the eye; one or two vertical series of scales separate the preoculars from the nasal, which is single or rarely divided, and hollowed out. Two series of scales between the eye and the labials. Upper labials eight to twelve, usually nine or ten, usually fourth and fifth below the eye. Temporal scales smooth or feebly keeled. Four or five lower labials in contact with the single pair of chin-shields.
VIPERA LEBETINA
After Sordelli
