Geitodoris planata (Alder & Hancock, 1846)

12 February, 2015.
Seven Step Reef, Loch Creran on the west coast. 
20 mm animal at 9 m - one of several seen. Water temperature 8°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