(pl. pleura, adj. pleural)
The lateral portion of a single thoracic segment in a trilobite (Trilobita). Each pleuron is indented by an oblique pleural furrow and the outer ends are downturned. The inner edges are attached to a central axial ring, so that each thoracic segment consists of a central axial ring and a pair of laterally placed pleura.
Subjects: Earth Sciences and Geography.