This is probably an unnatural group of nudibranchs that is in need of serious revision. The members of this group are united by having an oral veil, which probably originated independently in different Arminaceans. Other characteristics that are often associated with this group are a thickened mantle with extended margins and longitudinal ridges on the dorsum. These animals have been reported to feed on bryozoans (Janolus) and on soft corals and pentulaceans (Dermatobranchus).