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Thanks for identification to Terrence M. Gosliner. Terry wrote November 2003 he is working on it with his student Rebecca Johnson.
This species is Hypselodoris sp. 10 in IPN:
Gosliner, Terrence M., David W. Behrens & Ángel Valdés. 2008. Indo-Pacific Nudibranchs and Sea Slugs. Sea Challengers Natural History Books.
Gig Harbor, Washington. 426pp. at page 269
This species was posted on 15 December 2003 at these websites as Hypselodoris sp. A 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.