Onchidoris bilamellata (Linnaeus, 1767)

24 June, 2007.
Fast Castle, St. Abbs on the east coast.
A small 'swarm', one of many, on barnacle encrusted rocks at 12 m.
Water temperature 12° C.
Fuji 900 in Ikelite housing with Inon CU 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