Facelina auriculata (Müller, 1776)

19 August, 2001.
Godag reef off the island of Muck in the Inner Hebrides on the west coast.
Water temperature 13° C at 10 metres, a 28mm long individual on the kelp with a tiny (4mm) Polycera quadrilineata to the front and only noticed when the slide had been scanned. 
Nikonos 5 with 35 mm lens, 2:1 extension tubes and Ikelite 50 flash.

for more information about this species go to one of the links below
OPK - Opistobranquis

 nudibranchs of the british isles sea slug forum