Cryptolithus bellulus Ordovician Trilobite from Pennsylvania

Well-preserved example of a member of the Order Asaphida, Family Trinucleidae, with dramatically-displayed genal spines, a feature often not preserved intact. The cephalic pits (fenestrae) are also evident, the means by which this trilobite filtered detritus from the seafloor. The trilobite presumably hovered at the seafloor, using its legs to kick up particulates which then passed through the cephalic ring.