Arthrostraca \Ar*thros"tra*ca\, n. pl. [NL., fr. Gr. 'a`rqron
joint + ? a shell.] (Zool.)
One of the larger divisions of Crustacea, so called because
the thorax and abdomen are both segmented; Tetradecapoda. It
includes the Amphipoda and Isopoda.
[1913 Webster]