The early Redlichiida order had a simple glabella and small pygidium.
Their advanced eyes had structures similar to the Descartes and Huygens designs for minimal-aberration lenses. The early Redlichiida order had a simple glabella and small pygidium. Agnostida was smaller than a centimeter, and the other six orders of this class were the Corynexochida, Asaphida, Ptychopariida, Proetida, Lichida and Phacopida. Because their hard exoskeletons are easily preserved and dated, their fossils are often used as chronological markers. FTP, name this class of extinct "three-lobed" arthropods.
Their advanced eyes had structures similar to the Descartes and Huygens designs for minimal-aberration lenses.
trilobites [or Trilobita]