Hydrobranchiate

Hydrobranchiata Hy`dro*bran`chi*a"ta, n. pl. [NL., fr. Gr. "y`dwr water + ? gills.] (Zo["o]l.) An extensive artificial division of gastropod mollusks, including those that breathe by gills, as contrasted with the Pulmonifera. -- {Hy`dro*bran"chi*ate}, a. [1913 Webster]