http://slugsite.us/bow/doto_pa.htm
this website exists no more:
http://www.biology.ucsc.edu/classes/bio161l/NUDI/dkya.html
http://www.seaslugforum.net/factsheet.cfm?base=dotokya
http://www.medslugs.de/E/Pac-NE/Doto_kya.htm