Inferobranchiate

from The Collaborative International Dictionary of English v.0.48

Inferobranchiate \In`fe*ro*bran"chi*ate\, a. [L. inferus lower +
   E. branchiate.] (Zool.)
   Having the gills on the sides of the body, under the margin
   of the mantle; belonging to the Inferobranchiata.
   [1913 Webster]