Okenia nodosa (Montagu, 1808)

20 February, 2011.
Lephinchapel, Loch Fyne on the west coast.
6 mm animal, one of several including mating pairs at 12-18 metres. Water temperature 6° C.
Sony NEX-5 in Nauticam housing, 18-55mm lens and 2 x Inon D-2000 flashes.

for more information about this species go to one of the links below
OPK - Opistobranquis nudibranchs of the british isles sea slug forum