252 TRILOBITA CHAP. VIII 
Fam. 16. Lichadidae.——The body is broad, with a granular 
dorsal surface. The cephalic shield is small and short, with 
spinose genal angles. The glabella is \broad, and its anterior 
furrows are directed backwards, limiting \a convex median lobe 
and some lateral lobes. The facial suture extends from the 
posterior to the anterior margin. There aré.nine or ten thoracic 
segments with grooved pleurae, which have pointed ends. The 
pygidium is large and triangular, with a short axis and a toothed 
margin. Ordovician to Devonian. Genus: Lichas (sub-genera, 
Arges, Dicranogmus, Conolichas, Ceratolichas). 
