| amphibia | <zoology> One of the classes of vertebrates. The Amphibia are distinguished by having usually no scales, by having eggs and embryos similar to those of fishes, and by undergoing a complete metamorphosis, the young having gills. There are three living orders: (1) The tailless, as the frogs (Anura); (2) The tailed (Urodela), as the salamanders, and the siren group (Sirenoidea), which retain the gills of the young state (hence called Perennibranchiata) through the adult state, among which are the siren, proteus, etc.; (3) The Coecilians, or serpentlike Amphibia (Ophiomorpha or Gymnophiona), with minute scales and without limbs. The extinct Labyrinthodonts also belonged to this class. The term is sometimes loosely applied to both reptiles and amphibians collectively. See: Amphibium. Source: Websters Dictionary (01 Mar 1998) |
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| amphibian | <zoology> Of or pertaining to the Amphibia; as, amphibian reptiles. <zoology> One of the Amphibia. Source: Websters Dictionary (01 Mar 1998) |
| amphibian venoms | Venoms produced by frogs, toads, salamanders, etc. The venom glands are usually on the skin of the back and contain cardiotoxic glycosides, cholinolytics, and a number of other bioactive materials, many of which have been characterised. The venoms have been used as arrow poisons and include bufogenin, bufotoxin, bufagin, bufotalin, histrionicotoxins, and pumiliotoxin. (12 Dec 1998) |