Saurians, an order of scaly reptiles, including such as are popularly called lizards, skinks, monitors, geckos, iguanas, agamas, chameleons, etc., and the extinct iguanodon, ichthyosaurus, pterodactyl, and plesiosaurus. The ophisaurians, like the blindworm and amphis-baena, have no limbs, and form the connecting links between lizards and serpents. The sau-rians are all air-breathers, and the two lungs are about equally developed; the young undergo no metamorphosis, and the eggs are covered by a hard skin or shell; a few are viviparous. (See Lizard.) The anal aperture is transverse, and the dermal or external skeleton is not bony like that of the loricata or croco-dilians; the older writers, and some of the modern, place the crocodilians among saurians. This order is very numerous in genera and species, distributed most abundantly in tropical regions, where they are largest and most active. In their movements they come near the mammals, among them being found those which creep, others which walk, or run, or climb, or swim, or dive, or burrow, or fly.

Their important subdivisions are treated under the popular names.