In some specimens (var. _quadrilineatus_) the dorsal spots are replaced by two brown or red, black-edged stripes bordering a pale greyish or yellowish vertebral stripe (Plate VII., fourth figure); such specimens are so coloured from birth. This colour variety, which is so strikingly different from the typical form, is connected with the latter by the var. _schwoederi_, Werner, in which the spots form two vertebral series, and the var. _elsneri_, Werner, in which the light vertebral band is broken up by dark transverse bars, producing a ladder-like pattern.
_Size._--Rarely exceeding a length of 3 feet.
_Distribution._--Southern Italy, Sicily, Malta, Istria, Dalmatia, and other parts of the Balkan Peninsula, Grecian islands, Crimea, Asia Minor. The altitudinal range does not extend beyond 1,600 feet.
_Habits._--This is not only the prettiest European snake as regards its markings, whether in the form of spots or of stripes, but also the most graceful in its movements. Unless compelled to fly for safety, there is something slow and deliberate in its behaviour which is more suggestive of _Coronella_ than of most other species of _Coluber_. It is fond of climbing, and if the terrarium in which it is kept be provided with a bush or small tree, it will spend most of the time gracefully coiled round the branches. Usually very savage when fresh caught, some specimens become quite tame in captivity. In Dalmatia, where it is not uncommon, this snake is found principally among prickly shrubs, in hedges, or on old walls. It awakens from its winter slumber later than other South European snakes. Although occasionally taking lizards, its principal food consists of mammals and birds, which are killed before being devoured, the Leopard Snake being, like the other members of the genus _Coluber_, a constrictor.
_Reproduction._--According to Werner, the eggs, two to five in number, are deposited in midsummer; they are remarkably elongate: 2-1/2 inches long, 2/3 inch broad.
13. COLUBER SCALARIS, Schinz The Ladder Snake
_Form._--Moderately slender. Snout pointed, strongly projecting beyond the mouth. Tail one-sixth to one-fifth of the total length.
_Head-Shields._--Rostral deeper than broad, forming an acute angle above, wedged in between the internasals, the portion visible from above nearly as long as its distance from the frontal. Frontal about once and one-third to once and a half as long as broad, as long as or shorter than its distance from the end of the snout, nearly as long as the parietals. Loreal longer than deep. One pre- and two or three post-oculars. Temporals 2 + 3 or 2 + 4. Upper labials seven or eight (rarely nine), fourth or fourth and fifth (or fifth and sixth) entering the eye. Four or five lower labials in contact with the anterior chin-shields, which may be either longer or shorter than the posterior.