http://www.seaslugforum.net/showall/volvayak
http://www.umiushi.info/photo_species/photo_splist_eng.php?sopt=0&loc=0000
http://www.medslugs.de/E/Pac-NW/Volvatella_ayakii/Selection.htm
http://rfbolland.com/okislugs/volvayak.html
http://www.umiushi-zukan.com/eng/list_pic.php?ssw=g&kind_id=52