n. [ See Tethys. ] (Zool.) A tunicate. [ 1913 Webster ]
‖n. pl. [ NL., fr. Tethys + Gr.
n. [ NL., fr. Gr. &unr_; an oyster, or &unr_; a kind of ascidian. ] (Zool.) A genus of a large naked mollusks having a very large, broad, fringed cephalic disk, and branched dorsal gills. Some of the species become a foot long and are brilliantly colored. [ 1913 Webster ]