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The Collaborative International Dictionary
Thoracostraca

Thoracostraca \Tho`ra*cos"tra*ca\, n. pl. [NL. See Thorax, and Ostracoid, a.] (Zo["o]l.) An extensive division of Crustacea, having a dorsal shield or carapec? ??niting all, or nearly all, of the thoracic somites to the head. It includes the crabs, lobsters, shrimps, and similar species.