There are 6 main types of reptiles, Amphisbaenia (amphisbaenians), Sauria (lizards), Serpentes (snakes), Crocodylia (crocodiles), and Rhynchocephalia (tuataras). Amphisbaenians are usually legless and have long bodies, they are sometimes called snake worm lizards. Lizards are distinguished by having legs, movable eyelids, and external ear openings. Snakes are limbless and have have an elongated body and tail. Turtles have a shell that encloses most of their body. Crocodiles are a semiaquatic reptile with long jaws and a horny textured skin. The Rhynchocephalia order only includes one living species, the tuatara.