Polycera quadrilineata (Müller, 1776)

13 July, 2003.
Johnstone's Hole at Dunbar on the east coast.
Water temperature 12° C at 5metres, a pair of 25mm animals feeding on the bryazoan Membranipora membranacea growing on a kelp blade.
Olympus C-2020Z in Olympus PT-010 housing with +4 dioptre using the internal flash.

for more information about this species go to one of the links below
OPK - Opistobranquis nudibranchs of the british isles sea slug forum