TardigradaTar`di*gra"da\, n. pl. [NL. See Tardigrade, a.]1. (Zo["o]l.) A tribe of edentates comprising the sloths. They are noted for the slowness of their movements when on the ground. See Sloth, 3. 2. (Zo["o]l.) An order of minute aquatic arachnids; -- called also bear animalcules, sloth animalcules, and water bears.
|in some classifications considered a separate phylum: microscopic arachnid-like invertebrates living in water or damp moss having 4 pairs of legs and instead of a mouth a pair of stylets or needlelike piercing organs connected with the pharynx|