Knoutsodonta depressa (Alder & Hancock, 1842)

21 June, 2016.
Wuddy Rocks, St Abbs on the east coast.
10 mm animal at 16 metres. Water temperature 10C.
Sony α6000  in Nauticam housing, Zeiss 50 mm macro 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