A semi-aquatic mammal of the species Ornithorhynchus anatinus that lays eggs.
having a beak resembling that of a duck; "a duck-billed dinosaur"
primitive fish of the Mississippi valley having a long paddle-shaped snout
small densely furred aquatic monotreme of Australia and Tasmania having a broad bill and tail and webbed feet; only species in the family Ornithorhynchidae
