Paleëchinoidea

‖Pa′le‐ëch′i‐noi″de‐a (?), n. pl. [NL. See Paleo-, and Echinoidea.] (Zoöl.) An extinct order of sea urchins found in the Paleozoic rocks. They had more than twenty vertical rows of plates. Called also Palæechini. [Written also Palæechinoidea.]