Facelina auriculata (Müller, 1776)

1 March , 2011.
Portencross Pier, Firth of Clyde on the west coast. 
25 mm animal, one of several, on a pier leg at 3.5 m. 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