Hydrobranchiata \Hy`dro*bran`chi*a"ta\, n. pl. [NL., fr. Gr.
"y`dwr water + ? gills.] (Zool.)
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]