n. [ As if fr. a L. animalculum, dim. of animal. ] 1. A small animal, as a fly, spider, etc. [ Obs. ] Ray. [ 1913 Webster ]

2. (Zool.) An animal, invisible, or nearly so, to the naked eye. See Infusoria. [ 1913 Webster ]

☞ Many of the so-called animalcules have been shown to be plants, having locomotive powers something like those of animals. Among these are Volvox, the Desmidiacæ, and the siliceous Diatomaceæ. [ 1913 Webster ]

Spermatic animalcules. See Spermatozoa. [ 1913 Webster ]

{ } a. Of, pertaining to, or resembling, animalcules. “Animalcular life.” Tyndall. [ 1913 Webster ]

n. [ Cf. F. animalculisme. ] 1. (Biol.) The theory which seeks to explain certain physiological and pathological phenomena by means of animalcules. [ 1913 Webster ]

2. (Biol.) The theory that the spermatozoön and not the ovum contains the whole of the embryo; spermatism; -- opposed to ovism. [ Webster 1913 Suppl. ]

n. [ Cf. F. animalculiste. ] 1. One versed in the knowledge of animalcules. Keith. [ 1913 Webster ]

2. A believer in the theory of animalculism. [ 1913 Webster ]

‖n.; pl. Animalcula [ NL. See Animalcule. ] An animalcule. [ 1913 Webster ]

☞ Animalculæ, as if from a Latin singular animalcula, is a barbarism. [ 1913 Webster ]