Ra`di*a"ta (?), n. pl. [NL., fr. radiatus, p. p. See Radiate.] Zool.
An extensive artificial group of invertebrates, having all the parts arranged radially around the vertical axis of the body, and the various organs repeated symmetrically in each ray or spheromere.
⇒ It includes the c&oe;lenterates and the echinoderms. Formerly, the group was supposed to be a natural one, and was considered one of the grand divisions of the animal kingdom.
© Webster 1913.