http://www.gastropods.com/3/Shell_39613.shtml
http://www.marinelifephotography.com/marine/mollusks/gastropods/others/acteonidae.htm
http://www.underwaterkwaj.com/nudi/cephalaspideans/e198.htm
http://www.seaslugsofhawaii.com/species/Pupa-tessellata-a.html