Nektonic trilobites

Deiphon is a distinctive genus of Silurian phacopid trilobites of the family Cheiruridae found in Western and Central Europe, and in Central and Eastern United States. The type species, D. forbesi, from England, Bohemia, and Sweden, was discovered and described by the French paleontologist, Joachim Barrande in 1850.

Cyclopygidae is a family of asaphid trilobites from the Ordovician. Cyclopygids had an extratropical distribution, and there is evidence that they lived in darker parts of the water column (around 175m deep). Cyclopygids are characterized by enlarged eyes, with a wide angle of view, both horizontal and vertical, reminiscent of the eyes of dragonflies. These typically touch the glabella directly on the side. Cyclopygids all lack genal spines, but Symphysops carries a forward directed frontal spine on the glabella. It is presumed that at least the members of the genus Pricyclopyge swam upside do