Reptiles are cold-blooded vertebrates, ovipares depending on the rule, at pulmonary breathing. They have separate sexes; Their embryos have an amnios and an allantoid membrane, and are each contained in a more or less cylindrical egg, with membranous or parchment envelope. Reptiles are much more complex than fish by all traits of their organization, essentially earthly; None of them are completely aquatic: crocodiles, just like lizards and snakes, breathed with lungs and are forced to come from time to time to hove the air on the surface.