In 1921-22 amphibious tanks were produced in France and in America. The first amphibious tanks were designed during World War I.
It has a propeller engine, standard caterpillar treads (if it is a caterpillar vehicle), and water jets. (1) The amphibious tank and carrier can float because the hermetically sealed body displaces the necessary amount of water. Carroll, The Rise of Amphibians (2009).Ī combat or transport motor vehicle that can move on land and on water (tank, carrier, automobile, airplane). Frogs and toads are highly modified for jumping, with large, muscular hind legs and no tails, while the caecilians have lost all external traces of limbs. The salamanders and newts are superficially the most similar to ancestral amphibians, having long tails and front and hind legs of approximately equal size. Adult amphibians differ from reptiles in having moist skins, without scales or with small, hidden scales.Īll living amphibians are specialized for their way of life, none representing the main amphibian stock from which the reptiles evolved. Some amphibians lay their eggs in dry places, and the young undergo the larval stage within the egg, emerging as small adults in these the eggs have evolved various protective structures. The eggs are usually deposited in water or in a protected place where their moisture will be conserved they have neither shells nor the sets of membranes that surround the eggs of reptiles and other higher vertebrates. Typically amphibians undergo a metamorphosis from an aquatic, water-breathing, limbless larva (called a tadpole) to a terrestrial or partly terrestrial, air-breathing, four-legged adult.
Amphibians, the most primitive of the terrestrial vertebrates, are intermediate in evolutionary position between the fish and the reptiles. There are three living orders of amphibians: the frogs and toads (order Anura, or Salientia), the salamanders and newts (order Urodela, or Caudata), and the caecilians, or limbless amphibians (order Gymnophiona, or Apoda), a little known tropical group. Amphibian, in zoology, cold-blooded vertebrate animal of the class Amphibia.
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