The Grass Snake is our largest British species, full-grown females averaging four feet in length; the males a foot less. Exceptional examples are little short of six feet, and in Italy the same species attains to a length of eight feet. It is of graceful form, the body tapering gently from its middle to the very slender tip of the tail. The long, narrow head, covered with large shields, ends in a blunt snout, with eyes and nostrils at the sides. The rather large eyes have round pupils circled with gold and a dark brown iris. Just behind the head there are two patches of yellow or orange (sometimes white) forming a bright collar which serves to indicate this species at a glance. In large females this collar is sometimes missing. Immediately behind it are two patches of black, often united in the middle line, and behind these the ground colour of grey, olive, or brown is uniform to the tip of the tail. Upon the ground colour of the back are laid two rows of small blackish spots, and a row of short vertical bars along each side. The underside, which is covered with broad plates, is chequered in black and white (or grey); but is sometimes entirely black. The tail accounts for about one-fifth only of the total length. Apart from the head-shields and the broad plates of the underside, the Grass Snake is covered with nineteen rows of small, overlapping, lance-shaped scales with a central ridge or "keel." These scales are an outgrowth from the skin, and when the Snake moults they do not fall off as the hairs of fur-clad animals do, but the entire skin with its scales is cast intact. It separates first at the edges of the jaws, and the Snake pushes against the ground, stones, or plant stems until the loose skin is behind the head. Then it glides out of the remainder, reversing it in the process. In these discarded sloughs the lens-like covering of the eye will be found unbroken.