Facelina auriculata (Müller, 1776)

6 April, 2013.
Eagamol, Muck on the west coast. 
10 mm animal at 13 m. Water temperature 5.9°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