1) Gastropod 2) Sea slug 3) Univalve 1) Nudibranchiate 2) Seaslug 
clade Euthyneura clade Nudipleura clade Nudibranchia | subdivision_ranks = Clades | subdivision = A nudibranch k is a member of Nudibranchia, a group of soft-bodied, marine gastropod mollusks which shed their shell after their larval stage. They are noted for their often extraordinary colors and striking forms. There are more than 3,000 described ...
• (n.) One of the Nudibranchiata. • (a.) Of or pertaining to the Nudibranchiata. • (a.) Of or pertaining to the Nudibranchiata. • (n.) One of the Nudibranchiata.
any of the marine gastropods that constitute the order Nudibranchia (subclass Opisthobranchia of the class Gastropoda). Nudibranchs ... [7 related articles]
Nu'di·branch adjective (Zoology) Of or pertaining to the Nudibranchiata. -- noun One of the Nudibranchiata. 
nudibranch A mollusc of the order Nudibranchiata, having naked gills and no shell.
Shell-less marine snails.
a shell-less, marine snail of the suborder Nudibranchia, having external, often branched respiratory appendages on the back and sides.