While this may fall under the forms of Hypselodoris maculosa and could be a juvenile, it seems different enough to keep separate at this time. It also looks as though it could be a Thorunna, but a look at the internal anatomy would be required to verify it. This was found on the slope east of the Liberty wreck in Tulamben Bay in November 2015.
The photo below show what appear to be glandular structures in the posterior end.
Created 24 January 2016