Onchidoris bilamellata (Linnaeus, 1767)

18 October, 2014.
Eilean nan Coinean, Sound of Jura on the west coast. 
6 mm animal at 16 m with barnacle (maybe it's lunch!). Water temperature 14°C.
Sony α6000  in Nauticam housing, 50 mm Zeiss 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