Nudibranch Hypselodoris kanga
"I am pretty sure this is Hypselodoris kanga. The spots on the outer face of each gill are not clear but there is a double orange line which indicates the gills are triangular in cross-section. Now and then there are specimens in which the spots are not easy to see."
Australian Museum, Sydney
Locality: Lambeh strait, 15 m, Indonesia, North Sulawesi, Indopacific, 30 april 2006, Muck. Length: 50-70 mm.