sb. pl. [L. amphibia (sing. amphibium), a. Gr. ἀμφίβια, sing. ἀμφίβιον, living in both, and subst. (sc. animal, ζᾦον) an animal that lives in both elements; f. ἀμφί both + βίος life. The sing. forms amphibion, amphibium, were formerly in use, for which, in sense 4, AMPHIBIAN is now used.]
I. sing. amphibium, -on, with pl. -a, -ums.
1. A being that lives either in water or on land, or is equally at home in either element.
1609. Holland, Amm. Marcell., XXII. xv. 212. Some live on land and water both, whereupon they are named Amphibia.
1631. Whimzies, 85. A Sayler is … an amphibium that lives both on land and water.
1655. Fuller, Ch. Hist., IV. 136. Like an Amphibion, He was equally active on water, and land.
1667. Phil. Trans., II. 579. Could stay a great while under water, as Amphibiums use to do.
1865. Esquiros, Cornwall, 172. The boat can travel both on land and sea like Amphibia.
2. fig. A being of doubtful or ambiguous position.
1645. Whaly, Serm., in Southey, Comm.-Pl. Bk., II. (1849), 6. Ask these amphibia what names they would have. What, are you papists? no … are you protestants? no.
c. 1670. Marvell, Unfort. Lover, Wks. III. 243. He both consumed, and increas’d: And languished with doubtful breath Th’ amphibium of life and death.
3. A being having a double existence. rare.
1823. Lamb, Elia, Child Angel, 472. Humility and Aspiration went on even-paced in the instruction of the glorious Amphibium.
II. pl. only.
4. Zool. a. Applied by Linnæus to Reptiles in the wider sense (including Reptiles and Amphibia of mod. naturalists). Obs. b. By Cuvier to a tribe of Mammals including seals and their allies. c. By modern zoologists since Macleay (c. 1819), to the fourth great division of Vertebrata, intermediate between reptiles and fishes, which in their early state breathe by gills like fishes, as frogs, newts, etc.
a. 1753. Chambers, Cycl. Supp., Amphibia … a class of animals, whose essential characters are, that they have either a naked, or else a scaly body … their teeth being all sharp and pointed, and without radiated fins.
b. 1833. Sir C. Bell, Hand, 99. In the true Amphibia, as the phoca and walrus, we have the feet contracted, and almost enveloped in the skin, and the fingers webbed and converted into fins.
c. 1825. J. Gray (title), Synopsis of the Genera of Reptiles and Amphibia.
1841. Penny Cycl., XIX. 407/1. Gray … considers the Reptiles, or scaly-skinned group, and the Amphibia, or naked-skinned group, as distinct classes.
1859. Carpenter, Anim. Phys., ii. (1872), 90. Many Zoologists range the Frogs and their allies in a separate class under the name of Amphibia.
1870. Rolleston, Anim. Life, Introd. 61. Amphibia … cold blooded Vertebrata … provided with gills for aquatic in addition to lungs for aerial respiration.
