Dictionary.net

• A genus of oceanic nudibranchiate mollusks having the small branched gills situated on the upper side of four fleshy lateral lobes, and on the median caudal crest.

2010 - New Age Dictionary Database
By Oddity Software

• A genus of oceanic nudibranchiate mollusks having the small branched gills situated on the upper side of four fleshy lateral lobes, and on the median caudal crest.

1913 - Webster's Revised Unabridged Dictionary
By Noah Webster.