"This aeolid is one of several European species of the family Flabellinidae characterised by having the cerata arising in clusters from common stalks as can be seen very nicely in this photo - the genus Coryphella used to cover such species. Flabellina affinis itself is specifically characterised by having an opaque violet zone immediately below the cnidosac at the tip of each ceras, and this violet zone can just be made out in some of the cerata in this individual."