Felimare orsinii is a small to medium sized chromodorid
nudibranch present in the Mediterranean. It is usually
found roaming on a black sponge (Cacospongia mollior).
This species is uncommon and rarely encountered
because of its small size. It is sufficiently distinct to be
identified in the field.
Oral tentacles: 2 in number, very short. Rhinophores: Deep blue in colour, finely lamellate and
retractable. Cerata: Absent. Gills: Retractable, unipinnate, blue in colour. Body: Blue to dark blue without purplish tinge; a white to
yelllow line is present along the marginal edge whilst a
single white line is present in the middle of the notum. Foot: Blue with a lateral white line visible when viewed
sideways. The white line extends to the posterior part of
Size range: 8-30mm. Uncommon.
Specific characteristics: This species is easy to
distinguish from related species by its colouration.