This animal has been the subject of much discussion on the Sea Slug Forum lately with the consensus being that it is Dialula lentiginosa. Other possibilities include Doris montereyensis (possible, though gills are somewhat whitish, it only has 2 small spots and it does have a number of vague dark patches) Doris odhneri (unlikely due to the two small spots) and Geitodoris heathi (unlikely due to the large size of about 180-200mm).