Fig. 33 (From Proceedings of the Zoological Society, 1893)
Head-Shields.—Rostral as deep as broad or slightly deeper than broad, visible from above, in contact with one apical shield (rarely with two). Distinct frontal and (usually) parietal shields, the former once and a half to once and two-thirds (rarely once and one-third) as long as broad, as long as its distance from the rostral or the end of the snout, and nearly always longer than the parietals; the latter always in contact with the former, rarely broken up into small shields. Four to seven small shields on the snout between the canthals, of which there are two on each side. Supraocular well developed, extending posteriorly beyond the vertical of the eye, separated from the frontal by one to three shields, very rarely in contact with it. Six to ten scales round the eye, usually eight or nine, the upper preocular usually in contact with the nasal; a single series of scales between the eye and the labials. Nasal single. Temporal scales smooth. Upper labials six to nine, usually seven or eight, usually third or third and fourth below the eye. Three (rarely four) lower labials in contact with the chin-shields, of which there is but one pair.
Scales in nineteen (rarely twenty or twenty-one) rows, with two apical pits, strongly keeled on the back, less strongly on the sides, outer row smooth. Ventral shields 120 to 135 in males, 125 to 142 in females; anal entire; subcaudals 30 to 37 in males, 20 to 28 in females. By adding the subcaudals to the ventrals in a hundred specimens, the total numbers are 153 to 169 in males, 150 to 168 in females.
Coloration.—Unlike its ally V. berus, V. ursinii shows no sexual differences in the coloration. The ground colour of the back is usually yellowish or pale brown, sharply defined from the darker grey or brown colour of the sides; some specimens, however, are of an almost uniform brown ground colour. The light colour of the back is relieved by a series of more or less regular transversely oval, elliptic, or rhomboidal dark brown, black-edged spots, some or all of which may run together to form a wavy or zigzag band ([Plate XII].). Two or three longitudinal series of dark brown or black spots extend along the sides, the upper series, if present, occupying the space between the series of spots continued from the postocular band and the large dorsal spots or vertebral band, the lowermost following the outer row of scales. Small dark spots and one or two Λ-shaped markings are present on the upper surface of the head; an oblique dark band proceeds from the eye to the angle of the mouth, and is not infrequently confluent with the branches of the occipital Λ. The rostral and the labial shields are uniform yellowish-white, rarely with a few small, blackish spots or with brown borders. The chin and throat are yellowish-white, rarely with some blackish spots. The ventral and subcaudal shields are black, with transverse series of small white spots, or grey checkered with black and white, or whitish with small round black spots; the tail is but rarely (females) tipped with yellow.
The form recently described as V. macrops, Méhely, from Bosnia and Herzegovina, is distinguished by a usually larger eye, the vertical diameter of which equals or a little exceeds its distance from the mouth, and the parietals are often broken up into small shields. The postocular dark band is often reduced, originating at some distance from the eye, and is not prolonged beyond the mouth. In this geographical race melanic specimens occasionally occur, which are dark brown or blackish above, the lower parts not differing from those of the typical form.
Size.—20 inches appears to be the usual maximum size reached by this species, but, Dr. Werner informs me, a female 2 feet long has been found in Lower Austria.
Distribution.—First discovered in Italy in the Abruzzi, this species has since been found in the Basses-Alpes, near Digne, in various parts of Hungary, in Lower Austria, on the island of Veglia in Istria, and in Bosnia, Bulgaria, Herzegovina, and Montenegro. A very broken and curious distribution, the more so as V. ursinii is essentially a form of the plain in Lower Austria and Hungary, and an alpine form in Italy, in France, and in the Balkan Peninsula, where it only occurs between 3,000 and 6,800 feet. In no part of its habitat does it appear ever to be found in company with V. berus.
Habits.—Only a few specimens have hitherto been found in Italy and in France, but the species occurred up to a few years ago in extraordinary numbers in Lower Austria, in the immediate vicinity of Laxenburg. The intendant of the imperial castle pays a premium for the destruction of Vipers, and in the course of one year (1892) more than 1,000 specimens were brought to him. These snakes are found principally, though not exclusively, in the marshy meadows around the park, where they may be seen about in the daytime from May to September, feeding chiefly on lizards (Lacerta agilis), and also on small rodents. The lizards are swallowed as soon as seized, without the effect of the poison being awaited as in other Viperid snakes. This Viper is as a rule of gentle disposition, allowing itself to be handled without attempting to bite, and village boys have been seen playing with them. Although occurring in such enormous numbers at Laxenburg, no accident from snake-bite has ever been heard of. The form from the Balkan Peninsula (V. macrops) is even more pacific still, and is believed never to make use of its poison apparatus, its food consisting of orthopterous insects. According to Captain Veith, who has collected a large number of specimens of this Southern form, the contents of the stomach as well as the excrements show this snake to feed exclusively on grasshoppers. On one occasion a big specimen showed such a swelling of the body as to lead to the conclusion that it had swallowed a mouse, but it soon after disgorged what proved to be a ball made up of the agglutinated remains of at least a hundred grasshoppers. When handled, this Viper hisses or even pretends to snap, but with closed mouth, never biting unless seriously hurt. The poison appears to have little effect on man.