Click the thumbnail photos to enhance!
Thanks for identification to David W. Behrens.
This species is Hypselodoris sp. 3 in IPN at page 265:
Gosliner, Terrence M., David W. Behrens & Ángel Valdés. 2008. Indo-Pacific Nudibranchs and Sea Slugs. Sea Challengers Natural History Books.
Gig Harbor, Washington. 426pp.
Pretty similar are
Hypselodoris sp. 04 which has also bluish spots at the mantle magin, and brown longitudinal lines, it differs by the rhinophores: translucent white with two orange bands.
Hypselodoris sp. 05 which has also bluish spots at the mantle magin, it differs by opaque white longitudinal lines, and thin pale brownish longitudinal lines.
Hypselodoris sp. 06 which has also bluish spots at the mantle magin, it differs by the mottled background colour, and by translucent patches on the mantle near the rhinophores.
This species was posted at these websites on 11 February 2005 as Hypselodoris sp. B Genus: Stimpson, 1855.
For some genera, such as Trinchesia was the alphabet almost through. I had to change the distinguishing alphabetic character into a number. I have chosen 2-digit numbers, even though '01' looks a little bit stupid, and now is only the genus italic written.
More informations on Hypselodoris sp. 02 are at Mike Miller's Slug Site!