"This aeolid is one of several European species of the family Flabellinidae characterized 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 ischitana itself is specifically characterized by lacking any violet coloration on the surface of the cerata so that the internal digestive diverticulum can be seen throughout its length. In the very similar species, Flabellina affinis, there is an opaque violet zone immediately below the cnidosac at the tip of each ceras that obscures the digestive diverticulum."