gregarinae
Greg`a*ri"nae, n. pl. Etym: [NL., fr. Gregarina the typical genus, fr. L. gregarius. See Gregarious.] (Zoöl.) Defn: An order of Protozoa, allied to the Rhizopoda, and parasitic in other animals, as in the earthworm, lobster, etc. When adult, they have a small, wormlike body inclosing a nucleus, but without external organs; in one of the young stages, they are amoebiform; -- called also Gregarinida, and Gregarinaria.