Domain: Eukaryota-The Platypus has Eukaryota cells with membrane bound organelles.
The Platypus responds to stimuli and are multicellular organisms.
The Platypus has a ventral nerve cord, pharyngeal slits and a tail. There are also three subphyla of Chordata, the Platypus belongs in the Vertebrata.
The Platypus produces milk for the young through mammary glands like all mammals. It also is warm blooded and has three specialized bones in the ear for hearing, also it has no visible ears.
Order: Monotremata-A monotreme is simply a mammal that produces young by eggs instead of having live-birth.
Family: Ornithorhynchidae-The Platypus is the sole survivor of the whole family of the Ornithorhynchidae. They are characterized by having the duck-bill, a flat tail for swimming and have hard plates in the mouth, instead of teeth.
Genus: Ornithorhynchus-Any Ornithorhynchus is a member of the family, Ornithorhynchidae, in which case, it must be a Platypus!
Species: Ornithorhynchus anatinus