Dicellocephalus Minnesotenis a Trilobite
Trilobites ("three-lobes") are extinct marine arthropods that form the class Trilobita.The earliest trilobites had complex, compound eyes with lenses made of calcite, a unique characteristic of all trilobite eyes. The trilobite eyes were typically compound, with each lens being an elongated prism. The number of lenses in such an eye varied: some trilobites had only one, while some had thousands of lenses in a single eye. In these compound eyes, the lenses were typically arranged hexagonall (b).