The glass lizards or glass snakes are a genus, Ophisaurus (from the Greek 'snake-lizard'), of reptiles that resemble snakes, but are actually lizards. Although most species have no legs, their head shapes, movable eyelids, and external ear openings identify them as lizards. A few species have very small, stub-like legs near their rear vents. These are vestigial organs, meaning they have evolved and are no longer in use. These animals are also known as jointed snakes.