Palæont. [ad. mod.L. amphithērium (also in Eng. use), f. Gr. ἀμφί both, on both sides + θηρίον a beast; in reference to its disputed position in the animal series.] An extinct genus of small opossum-like quadrupeds, found in the Oolite.
1859. Owen, Classif. Mammalia, 55. The nearest living analogue to the amphitheres … of our oolitic strata. Ibid. (1864), Power of God, 50. The marsupial analogues of the amphitheria.
