nGastrostege(Zoöl) One of the large scales on the belly of a serpent.
Century Dictionary and Cyclopedia
ngastrostegeOne of the scales or scutes which cover the abdomen of a snake from the head to the tail; an abdominal scute or scutellum. Snakes seldom have on the belly many small scales like those of the back and sides, being usually furnished instead with short, wide, transverse gastrosteges which reach from side to side, and are imbricated, the hind edge of one overlapping the fore edge of the next succeeding. By muscular action when the snake is wriggling the whole series of gastrosteges stand somewhat on edge, so that their sharp hind borders catch on the slightest inequality of the surface, over which the snake thus glides as if pushed along by numberless little feet. That such is the action of the gastrosteges may be inferred from the ineffectual writhing of a snake when placed on a perfectly smooth surface, as a plate of glass. The last gastrostege, technically called the preanal or postabdominal, is usually bifid, or otherwise modified. Scutes somewhat like gastrosteges cover the under side of the tail, and are known as urosteges. See urostege.