phillipsia

from The Century Dictionary.

• noun A genus of opisthoparian trilobites of the family Proëtidæ, having small oval tuberculate carapaces with subcylindrical glabella provided with strong basal lobes, nine thoracic segments, and large multisegmented pygidium. It is the latest surviving genus of trilobites, ranging from the Lower Carboniferous into the Permian formations.