_Head-Shields._--Rostral once and a half to twice as deep as broad, nearly reaching the tip of the rostral wart. Upper surface of head covered with small, smooth or feebly keeled, subimbricate scales, among which a slightly enlarged frontal, or a frontal and a pair of parietals, may sometimes be distinguished; four to seven longitudinal series of scales between the supraoculars, which are large, and do not as a rule extend posteriorly beyond the vertical of the eye. Five or six (rarely three) scales on the posterior aspect of the raised part of the snout; two canthal scales on each side, the second in contact with the supraocular, or separated from it by the uppermost preocular. Eight to thirteen (usually nine to twelve) scales round the eye; two or three series of scales between the eye and the labials. Nasal hollowed out, entire, separated from the preoculars by one or two vertical series of scales; naso-rostral sometimes divided into two in North African specimens. Temporal scales smooth or feebly keeled. Upper labials nine to eleven (rarely eight), fourth and fifth (rarely third and fourth) below the eye. Four or five lower labials in contact with the single pair of chin-shields. _Scales_ in twenty-one rows, with two apical pits, strongly keeled, outer row smooth or feebly keeled. Ventral shields 125 to 146 in males, 135 to 147 in females; anal entire; subcaudals 35 to 45 in males, 32 to 38 in females. _Coloration._--Grey or brown above, the back often paler than the sides, with a broad darker, usually black-edged, wavy or zigzag band along the spine, and a lateral series of spots (Plate XIII.); the band sometimes replaced by large rhombic or transversely oval spots. Head with or without dark markings above, sometimes with two oblique dark streaks on the occiput; a dark streak from behind the eye to the first lateral spot, sometimes originating at a considerable distance from the eye; upper lip white or pale brown, more or less speckled or spotted with black. Lower parts grey, spotted with black and white, or blackish speckled with white, the end of the tail usually yellow or with yellow spots. _Size._--This Viper is not known to exceed a length of 2 feet. _Distribution._--Locally distributed over the greater part of Spain and Portugal, as far north as Burgos and Barcelona. Also found in Morocco near Tangier, and in Algeria near Bona and Guyotville. _Habits._--Lataste's Viper lives in stony and arid districts, and also in forests. The food consists chiefly of small mammals, but remains of a scorpion have been found in the stomach of an adult, and of a centipede in that of a young. According to Graells, this Viper easily climbs low trees in search of young birds, five of which have been found in the stomach of one specimen. The bite is believed to be less dangerous than that of _V. aspis_, and rarely causes the death of man and domestic animals.