Stephenson, 1920
Description
Diadumenidae with the column differentiated into scapus and capitulum, with a parapet and fosse which may smooth away in full extension. Only one type and size-range of p-mastigophore present in the acontia; macrobasic p-mastigophores occur in the tentacles of the sole British species, and in some foreign ones.
Type-species: Diadumene schilleriana (Stoliczka, 1869)