Catallacta \Cat`al*lac"ta\, n. pl. [NL., fr. Gr. ?. See {Catallactics}.] (Zo["o]l.) A division of Protozoa, of which {Magosph[ae]ra} is the type. They exist both in a myxopod state, with branched pseudopodia, and in the form of ciliated bodies united in free, spherical colonies.