Limacia clavigera (Müller, 1776)

3 April , 2011.
South Gortein, Loch Fyne on the west coast. 
25 mm animal, one of many, at 8 m. Water temperature 7°C.
Sony NEX-5 in Nauticam housing, 18-55mm lens, +10 SubSee 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