The Collaborative International Dictionary of English v.0.48:

Duck-billed platypus \Duck"-billed` plat"y*pus\, a.
   same as Duck Mole, under Duck..

   Syn: duck mole, duckbill, duck-bill platypus, platypus. [PJC]

WordNet (r) 3.0 (2006):

duckbilled platypus
    n 1: small densely furred aquatic monotreme of Australia and
         Tasmania having a broad bill and tail and webbed feet; only
         species in the family Ornithorhynchidae [syn: platypus,
         duckbill, duckbilled platypus, duck-billed platypus,
         Ornithorhynchus anatinus]