Nudibranchiata \Nu`di*bran`chi*a"ta\, n. pl. [NL. See {Nude},
and {Branchia}.] (Zool.)
A division of opisthobranchiate mollusks, having no shell
except while very young. The gills are naked and situated
upon the back or sides. See {Ceratobranchia}.
[1913 Webster]