Published online by Cambridge University Press: 01 May 2009
Regulaecystis devonica, which is probably from the Meadfoot Beds (Siegeman— Emsian) near Torquay, Devon, is characterized by smooth thick thecal plates and a deeply sunken pectinirhomb. Coopericystis Parsley from the Middle Ordovician of Tennessee is considered a junior synonym of Regulaecystis from the Lower Devonian of Europe.