tardigrada
Tar`di*gra"da, n. pl. Etym: [NL. See Tardigrade, a.] 1. (Zoöl.) Defn: A tribe of edentates comprising the sloths. They are noted for the slowness of their movements when on the ground. See Sloth, 3. 2. (Zoöl.) Defn: An order of minute aquatic arachnids; -- called also bear animalcules, sloth animalcules, and water bears.