I have no idea what this flatworm is. I happened to be diving down to retrieve some marine debris and noticed this on the way up under a cave ledge.  I took a quick photograph but it was in an awkward and dangerous spot and I couldn’t return safely in the surge. Apologies for the blurry image, but it was the best I could do. Cory Pittman response to my query as to identification: “I think you’d be safe calling this either a “euryleptid or pseudocerotid” based on the marginal tentacles. I suspect it’s a “scrunched up” euryleptid. It’s a bit reminiscent of “Euryleptid 17″ on Leslie’s CD.”  Update:  Another, very similar looking worm was spotted off of Black Rock, Maui in the summer of 2020. This may be Euryleptid 2.  See John Hoover’s Flatworms for more information and photos.