A small class of poorly known biflagellate unicellular algae (raphidomonads) in the chlorophyll a–c phyletic line (Chromophycota). It is sometimes called Chloromonadophyceae, and its members called chloromonads, but this nomenclature is confusing because it calls to mind Chloromonas, a totally unrelated genus of green algae (Chlorophyceae). The alternative nomenclature used here is derived from Raphidomonas, a generic name within the class.