http://www.habitas.org.uk/marinelife/species.asp?item=W14680
this website exists no more:
http://www.biology.ucsc.edu/classes/bio161l/NUDI/cconcinn.html
http://www.seaslugforum.net/showall/cuthconc
http://slugsite.us/bow2007/nudwk637.htm
http://www.nudibranch.org/Scottish Nudibranchs/cuthonella-concinna.html
http://www.medslugs.de/E/Atl-NE/Cuthonella_concinna/Selection.htm