Subphylum Trilobita
A group of extinct marine arthropods.
Ranged in size from a few millimeters up to 75 centimeters.
Body divided into three parts:
- cephalon (head), a single plate made up of several fused segments
- thorax, consists of a number of segments hinged together
- pygidium (tail), also segmented, but like the head, fused together into a single plate.
Compound eye, composed of radially arranged visual units