Facelina auriculata (Müller, 1776)

17 March , 2011.
Portencross Pier, Firth of Clyde on the west coast. 
A colourful pair of 35 mm animals, 2 of a group of 4 on a pier leg at 5.5 m. Water temperature 6°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