The intricate patterns on the body of this Gymnodoris are unbelievably complex and beautiful, especially in mature individuals.  Younger animals are a translucent creamy/white with orange dots and white spots or markings that are quite pronounced. As they get older the orangey-red lines seem to merge and squiggle, creating a map-like image when combined with the etchings of the acid glands that lie beneath the surface.   I’ve found that the gills are the most helpful identifier.   These animals have a full, frilly and beautiful circular gill, often ringed in white at the base.   For more information, see Sea Slugs of Hawaii.   Animals photographed here were all found in less than 2 metres (6 ft) of water in the Makena and North Kihei areas of Maui  and were no more than 1.25″ or 30 mm.