Onchidoris muricata (Müller, 1776)

19 April, 2003.
Rubh na Leime in the Lynne of Morvern on the west coast. 
At 20 metres one of several 9 mm animals observed on the reef. Water temperature 9 deg C.
Nikon 90SX with 105mm lens in Subal housing and housed SB26 flash.

for more information about this species go to one of the links below
scottish nudibranchs

 nudibranchs of the british isles sea slug forum