Agnostida genera

thumb|270x270px|Agnostus sp. from the Middle Cambrian of Couloma, Hérault, France. Max Rouger Collection.

species of trilobite

Geragnostus is a genus of very small agnostid trilobites whose fossils are found Ordovician-aged marine strata from Eurasia, North America and Argentina.

Acmarhachis is a genus of trilobites in the order Agnostida, which lived in what are now Australia (Queensland, Tasmania), Canada (British Columbia, Newfoundland, Northwest Territories), China (Anhui), Kazakhstan, Russia (Kharaulakh), and the US (Alaska, Alabama, Nevada, Maryland, Vermont). It was described by Resser in 1938, and the type species is Acmarhachis typicalis.