It’s probably unfair to give this beautiful aeolid the common name of “stick-bug” but that’s what struck me when I first saw it and Phyllodesmium sp. #1 is not an easy name to remember!. Though relatively small it is long and narrow with very long cerata.  Both these animals were found during the day, which apparently causes their cerata to swirl and blend a bit.  Look close and you will see lovely white markings, a bluish tinge to some and even some of their food prey (light brown octocoral) filling their cerata in tiny, branch-like patterns.  Found in the Heikili Point/Olawalu area of Maui in their typical habitat — less than 2 metres (6 ft) of water, in sea weed, octocoral and sand covered rubble. To 25mm or 1″.  For more information and photos, see Sea Slugs of Hawaii.