Polycera quadrilineata (Müller, 1776)

1 May, 2011.
Eilean Coltair, Loch Melfort on the west coast.
30 mm animal at 15 metres. Water temperature 9° 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