Polycera quadrilineata (Müller, 1776)

18 August 2001.
Loch nan Uamh near Arisaig on the west coast.
A 16 mm long animal on the kelp at 7 metres in 13° C water.
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