branchiogastropoda

from The Collaborative International Dictionary of English v.0.48

Branchiogastropoda \Bran`chi*o*gas*trop"o*da\, n. pl. [NL., from
   Gr. ? gill + E. gastropoda.] (Zool.)
   Those Gastropoda that breathe by branchi[ae], including the
   Prosobranchiata and Opisthobranchiata.
   [1913 Webster]