Wikipedia
Prestwichia (xiphosurans)
Prestwichia is an extinct genus of arthropods belonging to the order Xiphosura.
These palaeozoic arthropods, related to the modern king crabs and horseshoe crabs, lived in the Carboniferous period. They resemble the larvae of the modern Limulus.
Fossils of species within this genus have been found in the sediments of England.