Duvaucelia lineata (Alder & Hancock, 1848)

August 2000.
At Dunbar on the east coast.
During a mid morning dive a couple of dozen of this species were found on a single rock surface at 9 - 10 metres. The animals ranged in size from 10 to 25 mm in length.
for more information about this species go to one of the links below
OPK - Opistobranquis nudibranchs of the british isles sea slug forum