|The family Plakobranchidae
(listed as Elysiidae in some sources) includes shell-less species
with flap-like parapodia
extending over the
sides of their bodies. The parapodia contain
branches of the digestive
gland and also function in respiration. Many species retain
chloroplasts as kleptoplastids and some may show substantial
variation in morphology based on differences in diet or associated
chloroplasts. They may be either diurnal or nocturnal. There are at
least 27 species known from Hawaii in four
genera (Bosellia, Elysia, Plakobranchus
and Thuridilla). The family Boselliidae has been sunk into Plakobranchidae.
Thuridilla hoffae is listed for
French Frigate Shoals from a pre-2006 cruise but we lack
confirmation for the record.