Placodermi

‖Plac′o‐der″mi (?), n. pl. [NL., fr. Gr. πλάξ, πλακόσ, a tablet + δέρμα skin.] (Paleon.) An extinct group of fishes, supposed to be ganoids. The body and head were covered with large bony plates. See Illust. under Pterichthys, and Coccosteus.