海鞘类
Ascidian \As*cid"i*an\, n. [Gr. ? bladder, pouch.] (Zo["o]l.) One of the Ascidioidea, or in a more general sense, one of the Tunicata. Also as an adj.
ascidian n : minute sedentary marine invertebrate having a saclike body with siphons through which water enters and leaves