Fig. 1 in Enrolment in a Middle Ordovician agnostoid trilobite

Fig. 1. Trinodus elspethi (Raymond, 1925), silicified specimens from Edinburg Formation, Virginia, USA. A. PMO 206.303/1, dorsal view of holaspid cephalon. B. PMO 206.303/2, ventral view of holaspid cephalon; the posterolateral notch accommodates the anterior border of the pygidium during enrolment. C. PMO 206.304/1, dorsal view of first thoracic segment. D. PMO 206.304/2, ventral view of first thoracic segment. E. PMO 206.305, dorsal view of second thoracic segment. F. Ventral view of second thoracic segment; note articulating half−ring. G. PMO 206.306/1, dorsal view of pygidium. H. PMO 206.306/2, ventral view of pygidium with socket for posterior prong of second thoracic segment.