The Monotremata are represented at the present day in Australia and New Guinea by the _Echidna_ or Spiny Anteater, and by the _Ornithorhynchus_ or Duck-billed Platypus of Eastern Australia and Tasmania. These egg-laying mammals show relationship towards the reptiles both in structure and in methods of reproduction. A Pliocene species of _Ornithorhynchus_ (_O. maximus_) has been recorded from the Deep-leads of Gulgong, New South Wales, and the same beds have yielded the remains of _Echidna (Proechidna) robusta_. Remains of another species, _Echidna, (P.) oweni_, have been described from the Pleistocene Cave-breccias of the Wellington Valley Caves, New South Wales; and _Ornithorhynchus agilis_ is found in deposits of similar age in Queensland. =Marsupials.--= The Marsupials or pouched mammals belong to the sub-class Metatheria. They are divided into Diprotodontia and Polyprotodontia, accordingly as they possess a single pair of incisor teeth in the lower jaw, or many front teeth, hence the names of the two sub-orders. A later classification of the Marsupials is that of their division into syndactyla and diadactyla. The diadactyla have the second and third toes separate, and are represented by the family Dasyuridae or Native Cats. These are polyprotodont. They are the most archaic of the marsupial group. Remains of _Dasyurus_, both of extinct and still living species are found in Pleistocene Cave-breccias in Victoria and New South Wales. The Tasmanian Devil (_Sarcophilus ursinus_) (Fig. 138, 139) and the Tasmanian Wolf (_Thylacinus cynocephalus_), still living in Tasmania, have left numerous remains on the mainland, in Victoria and New South Wales. Of the latter genus an extinct species is _T. major_ from the Pleistocene of Queensland (Fig. 140). [Illustration: =Fig. 139= =Skeleton of Sarcophilus ursinus, Harris sp. (Tasmanian devil).= (_F. J. Moore, prep._) ] [Illustration: =Fig. 140= =Skull of Sarcophilus ursinus, Harris sp. (Tasmanian devil).= Pleistocene. Queenscliff, Victoria. About 1/2 nat. size (_After McCoy_). ] The syndactyla have the second and third toes enclosed in a common skin. The Peramelidae and the Notoryctidae are polyprotodont. The remainder are all diprotodont. The Peramelidae or Bandicoot family are represented in Pleistocene Cave-breccias in New South Wales by the genera _Peragale_ and _Perameles_. [Illustration: =Fig. 141--Thylacinus major, Owen.= Hind part of mandible, outer side. Pleistocene. Queensland. 1/2 nat. size] =Pleistocene Diprotodonts.--=