AMPHIBIA, a zoological term originally employed by Linnaeus to denote a class of the Animal Kingdom comprising crocodiles, lizards and salamanders, snakes and Caeciliae, tortoises and turtles and frogs; to which, in the later editions of the Systema Naturae he added some groups of fishes. In the Tableau Elementaire, published in 1795, Cuvier adopts Linnaeus's term in its earlier sense, but uses the French word "Reptiles," already brought into use by Brisson, as the equivalent of Amphibia. In addition Cuvier accepts the Linnaean subdivisions of Amphibia-Reptilia for the tortoises, lizards (including crocodiles), salamanders and frogs; and Amphibia-Serpentes for the snakes, apodal lizards and Caeciliae.
In 17991 Alexandre Brongniart pointed out the wide differences which separate the frogs and salamanders (which he terms Batrachia) from the other reptiles; and in 1804 P. A. Latreille,2 rightly estimating the value of these differences, though he was not an original worker in the field of vertebrate zoology, proposed to separate Brongniart's Batrachia from the class of Reptilia proper, as a group of equal value, for which he retained the Linnaean name of Amphibia.
Cuvier went no further than Brongniart, and, in the Regne Animal, he dropped the term Amphibia, and substituted Reptilia for it. J. F. Meckel,3 on the other hand, while equally accepting Brongniart's classification, retained the term Amphibia in its earlier Linnaean sense; and his example has been generally followed by German writers, as, for instance, by H. Stannius, in that remarkable monument of accurate and extensive research, the Handbuch der Zootomie (2nd ed., 1856).
In 1816, de Blainville,4 adopting Latreille's view, divided the Linnaean Amphibia into Squamiferes and Nudipelliferes, or Amphibiens; though he offered an alternative arrangement, in which the class Reptiles is preserved and divided into two subclasses, the Ornithoides and the Ichthyoides. The latter are Brongniart's Batrachia, plus the Caeciliae, whose true affinities had, in the meanwhile, been shown by A. M. C. Dumeril; and, in this arrangement, the name Amphibiens is restricted to Proteus and Siren.
B. Merrem's Pholidota and Batrachia (1820), F. S. Leuckart's Monopnoa and Dipnoa (1821), J. Muller's Squamata and Nuda (1832), are merely new names for de Blainville's Ornithoides and Ichthyoides, though Muller gave far better anatomical characters of the two groups than had previously been put forward.
Moreover, following the indications already given by K. E. von Baer in 1828,5 Muller calls the attention of naturalists to the important fact, that while all the Squamata possess an amnion and an allantois, these structures are absent in the embryos of all the Nuda. An appeal made by Muller for observations on the development of the Caeciliae, and of those Amphibia which retain gills or gill-clefts throughout life, has unfortunately yielded no fruits.
In 1825 P. A. Latreille6 published a new classification of the Vertebrata, which are primarily divided into Haematherma. containing the three classes of Mammifera, Monotremata and Aves; and Haemacryma, also containing three classes- Reptilia, Amphibia and Pisces. This division of the Vertebrata into hot and cold blooded is a curiously retrograde step, only intelligible when we reflect that the excellent entomologist had no real comprehension of vertebrate morphology; but he makes some atonement for the blunder by steadily upholding the class distinctness of the Amphibia. In this he was followed by Dr J. E. Gray; but Dumeril and Bibron in their great work,7 and Dr Gunther in his Catalogue, in substance, adopted Brongniart's arrangement, the Batrachia being simply one of the four orders of the class Reptilia. Huxley adopted Latreille's view of the distinctness of the Amphibia, as a class of the Vertebrata, co-ordinate with the Mammalia, Aves, Reptilia and Pisces; and the same arrangement was accepted by Gegenbaur and Haeckel. In the Hunterian lectures delivered at the Royal College of Surgeons in 1863, Huxley divided the Vertebrata into Mammals, Sauroids and Ichthyoids, the latter division containing the Amphibia and Pisces. Subsequently he proposed the names of Sauropsida and Ichthyopsida for the Sauroids and Ichthyoids respectively.
Sir Richard Owen, in his work on The Anatomy of Vertebrates, followed Latreille in dividing the Vertebrata into Haematotherma and Haematocrya, and adopted Leuckart's term of Dipnoa for the Amphibia. T. H. Huxley, in the ninth edition of this Encyclopaedia, treated of Brongniart's Batrachia, under the designation Amphibia, but this use of the word has not been generally accepted. (See BATRACHIA.) (T. H. H.; P. C. M.)
1 Brongniart's Essai d'une classification naturelle des reptiles was not published in full till 1803. It appears in the volume of the Memoires presentes a l'Institut par divers savans for 1805.
2 Nouveau dictionnaire d'histoire naturelle, xxiv., cited in Latreille's Fannilles naturelles du regne animal."
3 System der vergleichenden Anatomie (1821).
4 "Prodrome d'une Nouvelle Distribution du regne Animal." Bulletin des sciences par la Societe Philomatique de Paris (1816), p. 113.
5 Entwickelungs-Geschichte der Thiere, p. 262
6 Familles naturelles du regne animal.
7 Erpetologie generale, ou histoire naturelle complete des reptiles (1836).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)