_Head-Shields._--Rostral at least twice as broad as deep, not or but scarcely visible from above. Internasals as long as or a little shorter than the prefrontals. Frontal not much broader than the supraocular in the adult, once and a half to twice as long as broad, as long as or longer than its distance from the end of the snout, shorter than the parietals. Nasal usually semidivided. Loreal once and a half to twice as long as deep. One preocular, extending to the upper surface of the head, but not reaching the frontal; two (rarely one or three) postoculars. Temporals 1 + 2. Upper labials eight, fourth and fifth entering the eye, sixth usually in contact with the parietal. Four or five lower labials in contact with the anterior chin-shields, which are as long as or a little shorter than the posterior. _Scales_ with mostly single apical pits, the pits sometimes paired on the sides of the body, in twenty-one or twenty-three rows (nineteen to twenty-five in North African specimens). Ventral shields 153 to 192; anal divided; subcaudals 40 to 54. _Coloration._--Pale brown or greyish above, with small dark brown or blackish spots or with more or less distinct darker and lighter longitudinal streaks. Upper surface of head with dark brown vermiculations; a dark brown or black, often light-edged occipito-nuchal band, extending downwards to the gular region and produced forwards into a point to between the parietal shields; a dark brown or black streak on each side of the head from the end of the snout, through the eye, to the last lower labial shield, traversing the four last upper labials, which are yellowish above and below the streak (Plate XI.). Lower parts yellow or coral red, with black spots, which may form a tessellated pattern, two longitudinal series, or be so crowded as to fuse into a band along the middle of the belly and tail. The above description is taken from Spanish specimens (Badajos, Algeciras, Andalucia), but the variations are very great when we take North Africa into consideration. The nuchal band may be narrow or broken up into spots, the median of which sometimes forms a longitudinal streak, or so much enlarged as to fuse with the dark markings on the upper surface of the head; in some specimens (from Morocco and Algeria) the upper surface of the head and the nape may be entirely ink black, or the whole head black above and beneath with the exception of a whitish streak bordering the upper lip. The dark streak from the eye to the angle of the mouth may be absent, or reduced to a short oblique streak below the eye. Irrespective of the variations in the markings of the upper parts, the lower parts may be more or less spotted with black, or immaculate.