"Could be Phyllidia madangensis, although from specimens I've seen in the Marshalls, it can be impossible to tell Phyllidia madangensis from Phyllidia carlsonhoffi from the dorsum alone. A black line running lengthwise along the middle bottom of the foot would make it Phyllidia carlsonhoffi; lack of that line would make it Phyllidia madangensis. In some areas, Phyllidia madangensis appears to have a small tubercle at the anterior edge of the rhinophore pocket, that does not appear to be the case in the Marshalls, an island group close to Kosrae."