Defn: One of the orders of Branchiopoda. See Branchiopoda.

ARTHROSIS
Ar*thro"sis, n. Etym: [NL., fr. Gr. (Anat.)

Defn: Articulation.

ARTHROSPORE
Ar"thro*spore, n. [Gr. joint + E. spore.] (Bacteriol.)

Defn: A bacterial resting cell, — formerly considered a spore, but now known to occur even in endosporous bacteria. — Ar`thro*spor"ic (#), Ar*thros"po*rous (#), a.

ARTHROSTRACA
Ar*thros"tra*ca, n. pl. Etym: [NL., fr. Gr. (Zoöl.)

Defn: One of the larger divisions of Crustacea, so called because the thorax and abdomen are both segmented; Tetradecapoda. It includes the Amphipoda and Isopoda.

ARTHROTOME
Ar"thro*tome, n. [Gr. joint + to cut.] (Surg.)

Defn: A strong scalpel used in the dissection of joints.

ARTHROZOIC
Ar`thro*zo"ic, a. Etym: [Gr. (Zoöl.)