The Collaborative International Dictionary of English v.0.48:

Caducibranchiate \Ca*du`ci*bran"chi*ate\, a. [L. caducus falling
   (fr. cadere to fall) + E. branchiate.] (Zool.)
   With temporary gills: -- applied to those Amphibia in which
   the gills do not remain in adult life.
   [1913 Webster]