ASCIDIAN

[as.cid.i.an] n [NL Ascidia, group comprising tunicates, fr. Ascidium, genus name, fr. Gk askidion, dim. of askos wineskin, bladder] (1856): any of a class (Ascidiacea) of solitary or colonial sessile tunicates that have an oral and an atrial siphon--called also sea squirt