What is "acastoidea"

Acastoidea is a superfamily of trilobites from the order Phacopida, suborder Phacopina. This superfamily is divided into two families, Acastidae and Calmoniidae. This superfamily is distinguishable from the Phacopidae in that eyes are closer to the glabella and that the glabella has lobes, unlike the genera in Phacopidae.