The Collaborative International Dictionary of English v.0.48:

Abranchiate \A*bran"chi*ate\, a. (Zool.)
   Without gills.
   [1913 Webster]

WordNet (r) 3.0 (2006):

abranchiate
    adj 1: having no gills [syn: abranchiate, abranchial,
           abranchious, gill-less] [ant: branchiate, gilled]