Cephalon (head): The cephalon of trilobites bore various appendages, including antennae, and compound eyes composed of numerous individual lenses, providing them with a wide field of vision. Also present were organs capable of feeding and detecting smells. Some species also developed spines on their cephalon
Thorax: This section was composed of multiple articulated segments, usually between 2 to 40. Each segment had paired joint appendages used for walking, locomotion, or swimming The legs typically possessed hooks, spikes, or setae. While in some species some of the limbs were modified into gills
Pygidium (tail): Formed by the fusion of a varying number of posterior thoracic segments The shape and size of the pygidium were significant diagnostic features in trilobite identification, showcasing a diverse array