Facelinidae includes many of the larger Hawaiian aeolids. The body is
usually elongate and the cerata are usually arranged in rows or arches.
Most species feed on hydroids. However, the genus Favorinus specializes in eating the
of other opisthobranchs and the genus Phyllodesmium
eats octocorals. Most species retain the nematocysts from their food in
cnidosacs at the tips of their cerata and many also retain functional
zooxanthellae, derived from their food, in specialized branches of the
digestive gland. There are about 33 Hawaiian species in at
least 14 genera (Antonietta, Caloria,
Cratena, Facelina, Facelinella, Favorinus, Glaucus, Godiva, Herviella, Noumeaella, Phyllodesmium,
Pleurolidia, Pteraeolidia and Sakuraeolis).
The family was recently revised to
include the families Cratenidae, Glaucidae and Pteraeolididae.