Doto pinnatifida (Montagu, 1804)

30 September, 2012.
Eilean Alisdair, Loch Nevis on the west coast. 
20 mm animal at 15 m. Water temperature 13°C.
Sony NEX-5 in Nauticam housing, 18-55mm lens, SubSee +10 dioptre 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