|
Primitive trilobites with numerous thoracic segments with spinose tips. Cephalon large and semicircular; glabella typically long, well-segmented, tapering or expanding forwards; genal spines typically present, strong, usually continued from a narrow, tubular cephalic border; eyes typically large, crescentic, with large, inflated palpebral lobe ridges running toward front of glabella (anterior of S3); eye ridge may be subdivided. Thorax with numerous segments (up to 90+), pleurae usually with spinose tips; may be subdivided into prothorax and opisthothorax. Pygidium typically tiny (micropygous), one or very few segments.
From: http://www.trilobites.info/ordredlichiida.htm
|
Club Paleontologico Italiano