Flabellina pellucida (Alder & Hancock, 1843)

9 March, 2008.
The wreck of the SS Thesis, Sound of Mull on the west coast. 
A 30 mm long animal at 16 metres. Water temperature 8°C.
Fuji E900 camera in Ikelite housing with 2 x Inon CU lenses and 2 x Inon D-2000 flashes.