'Thoracostraca' definitions:

Definition of 'Thoracostraca'

From: GCIDE

Thoracostraca \Tho`ra*cos"tra*ca\, n. pl. [NL. See Thorax, and Ostracoid, a.] (Zool.) 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. [1913 Webster]