[Illustration: FIG. 27 (after Sordelli)] _Head-Shields._--Rostral at least as deep as broad, more or less produced posteriorly between the internasals, the portion visible from above at least half as long (in some specimens quite as long) as its distance from the frontal, rarely separating the internasals. Frontal once and one-fourth to once and a half as long as broad, much broader than the supraocular, as long as or longer than its distance from the end of the snout, shorter than the parietals, widely separated from the preocular. Nasal rarely undivided; loreal longer than deep. One (very rarely two) pre- and two postoculars. Temporals 2 + 2 or 2 + 3 (very rarely 1 + 2). Upper labials seven (rarely eight), third and fourth (or fourth and fifth) entering the eye. Four lower labials (rarely three) in contact with the anterior chin-shields, which are as long as or longer than the anterior. _Scales_ with one or two apical pits, the pit usually single on the back and paired on the sides, in nineteen (rarely twenty-one) rows.[B] Ventral shields 153 to 199; anal divided (rarely entire); subcaudals 41 to 70. _Coloration._--Grey, brown, or reddish above, with small blackish, dark brown, or brick-red spots usually disposed in pairs, sometimes forming cross-bars; sometimes with one or three lighter stripes; one or two black dots precede on each scale the single or paired apical pit; frequently two blackish, dark brown, or brick-red stripes on the nape, usually confluent with a large dark blotch on the occiput; the top of the head occasionally nearly entirely blackish, especially in the young; a dark streak on each side of the head, from the nostril to the angle of the mouth, passing through the eye, sometimes extending along the side of the neck or even of the whole body. Lower parts red, orange, brown, grey, or black, uniform or speckled or closely spotted with black and white, the sides often lighter (Plate IX.). A colour variety, of which I have examined a single specimen from near Vienna, is pale brown above, with four black lines along the anterior part of the body, and two small, yellowish, dark-edged spots close together on the back of the head, separated by the suture between the parietal shields.