Amphibia (BATRACHIA, SALAMANDERS AND FROGS)

Cold blooded Vertebrates, usually with naked skin, with lungs (and also gills, at least in the larva), with two chambers to the auricle in the adult and with a one-chambered ventricle to the heart. There are four pairs of aortic arches, the three anterior of which bear gills, the fourth being connected with the lungs. The eggs usually are fertilized and develop outside the body, the young having neither amnion nor allantois. There are four orders: Gym no phi on a, Labyrinthodont a, Urodela and Anura. Scientifically, this group of animals may be cla ed with the fishes, the two cla es being the phylum Ichthyopsid a. Popularly they are regarded as reptiles, the terms Salamander and Lizard being used without discrimination, and applied to apparently similar representatives of the Sauropsidan and Ichthyopsidan branches of Vertebrata.