Isopoda n. pl. (Zool.) An order of sessile-eyed Crustacea, usually having seven pairs of legs, which are all similar in structure. Note: The body is usually depressed, with the abdominal segments short, and often consolidated in part. The branchiae are on the abdominal appendages. The group includes the terrestrial pill bugs and sow bugs, with numerous marine forms. See Arthrostrata, Gribble.
