Superorder Lepidosauria , with scaly skins. Modern snakes, lizards, and tuataras. Two pairs of legs and external ear opening behind the eye. Geckos, iguanas, chameleons, etc. Suborder Serpentes , the snakes.
Snakes are elongate and limbless, although vestigial pelvis often present, and external ear absent.
Venom glands are modified salivary glands, with a mixture of toxins. 5 Suborder Amphisbaenia , the worm lizards. 135 species of specialized burrowers. The living fossil tuatara from New Zealand. Well-developed pineal eye gland.