_Form._--Slender; snout obtuse, feebly prominent. Tail one-fifth to one-fourth of the total length. [Illustration: FIG. 21 (after Sordelli)] _Head-Shields._--Rostral once and one-third to once and a half as broad as deep, the portion visible from above measuring about one-fourth to one-third its distance from the frontal. Frontal bell-shaped, considerably broader in front than the supraocular, once and one-fourth to once and a half as long as broad, as long as or a little longer than its distance from the end of the snout, shorter than the parietals. Loreal longer than deep, sometimes divided into two. One preocular (sometimes divided into two), in contact with the frontal; two postoculars; a series of three or four suboculars, usually completely separating the eye from the labials. Temporals 2 + 3 or 3 + 3. Eight or nine (rarely ten) upper labials, fifth or sixth very rarely entering the eye. Four lower labials in contact with the anterior chin-shields, which are shorter than the posterior. _Scales_ with two apical pits, in twenty-five to twenty-nine rows, usually twenty-seven. Ventral shields very distinctly angulate laterally, 222 to 258; anal divided (rarely entire); subcaudals 77 to 107. _Coloration._--Brown, pale olive, reddish, yellow, or orange above, with a dorsal series of large dark brown, black-edged rhomboidal spots, often bordered with yellow, on each side of which is a series of smaller, alternating spots (Plate V.); these spots may become entirely black in the adult, and so large as to reduce the ground colour to a mere network or series of X-shaped pale lines. A dark cross-band between the eyes, and a [V]- or horseshoe-shaped band on the back of the head, which may be confluent with an elongate spot on the nape; a light circle often present in the middle between the parietal shields. The spots often more or less confluent into three longitudinal streaks on the tail. Yellow, orange, or red beneath, with or without black dots, but constantly with a lateral series of black spots, which may be very large or unite with the spots higher up on the sides to form vertical bars. _Size._--Examples 5 feet long are on record; the largest examined by me measures 4 feet 3 inches. _Distribution._--Spain and Portugal, Sardinia, Pantellaria, Morocco, Algeria, Tunisia. Does not reach the North of Spain nor penetrate into the Sahara. _Habits._--This very handsome snake is as a rule as irascible as its European congeners. In Spain as well as in Algeria it is often found about the dwellings of man, occasionally entering houses in search of mice, on which it principally feeds; it is also fond of birds, and, climbing with great facility, plunders the nests of sparrows in towns and villages. It must be regarded as a useful commensal of man, and deserving of protection. _Reproduction._--F. Doumergue found in a hole in a rock near Oran, in September, the recently-laid eggs, five in number and as large as pigeons'.