unclassified flatworm

Spotted on coral while diving of Leeward Oahu; the location shown is notional. Month and day shown are notional; the year is known with certainty. The flatworm was in the process of crawling around two stalks of alga, Neomeris annulata, which creates the illusion in the uploaded image that the stalks were part the flatworm, its gill structures--which in turn would have made it a nudibranch! The image also creates another illusion, that the flatworm has one end (its right end) that is of a different color and texture than the rest of it. In fact, the flatworm ends just about where the green structures are, and everything to the right and below those structures in the image (that differently colored and textured material) is beneath the flatworm. Thanks to Cory Pittman for providing the identification of both the flatworm and the alga. Original medium color negative film; imaged with Nikonos III using close-up kit and flash. A print made from the negative was subsequently scanned and the image saved as digital file.