Trilobite anatomy

The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen.

right|thumb|222px|Diagram showing the location of the Cephalon (arthropod head)|cephalon, [[thorax and pygidium of a trilobite.]] The pygidium (: pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is composed of fused body segments, sometimes with a tail, and separated from thoracic segments by an articulation.

locomotory appendage of arthropods

the head section of an arthropod