Eubranchus farrani (Alder & Hancock, 1844)

18 October, 2015.
Nipple Rock, Hoy in the Orkney Islands.
10 mm animal at 15 metres. Water temperature 11°C.
Sony ?6000  in Nauticam housing, Zeiss 50 mm macro lens and 2 x Inon D-2000 flashes.