Cuthona nana (Alder & Hancock, 1846)

7 October, 2012.
7 Step Reef, Loch Creran on the west coast.
20 & 15 mm animals found on a hermit crab shell at 5 metres. Water temperature 12.5°C.
Sony NEX-5 in Nauticam housing, 18-55mm lens and Inon D-2000 flash.

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