More distinct is the Papuan genus _Dorcopsis_, as typified by _D. muelleri_, although it is to some extent connected with _Macropus_ by _D. macleyi_. The muzzle is naked, the fur on the nape of the neck directed more or less completely forward, and the hind-limbs are less disproportionately elongated. Perhaps, however, the most distinctive feature of the genus is the great fore-and-aft length of the penultimate premolar in both jaws. Other species are _D. rufolateralis_ and _D. aurantiacus_. In the tree-kangaroos, which include the Papuan _Dendrolagus inustus_, _D. ursinus_, _D. dorianus_, _D. benetianus_ and _D. maximus_, and the North Queensland _D. lumholtzi_, the reduction in the length of the hind-limbs is carried to a still further degree, so that the proportions of the fore and hind limbs are almost normal. The genus agrees with _Dorcopsis_ in the direction of the hair on the neck, but the muzzle is only partially hairy, and the elongation of the penultimate premolar is less. These kangaroos are largely arboreal in their habits, but they descend to the ground to feed. Lastly, we have the banded wallaby, _Lagostrophus fasciatus_, of Western Australia, a small species characterized by its naked muzzle, the presence of long bristles on the hind-feet which conceal the claws, and also of dark transverse bands on the lower part of the back. The skull has a remarkably narrow and pointed muzzle and much inflated auditory bullae; while the two halves of the lower jaw are firmly welded together at their junction, thus effectually preventing the scissor-like action of the lower incisors distinctive of _Macropus_ and its immediate allies. As regards the teeth, canines are wanting, and the penultimate upper premolar is short, from before backwards, with a distinct ledge on the inner side. In the rat-kangaroos, or kangaroo-rats, as they are called in Australia, constituting the sub-family _Potoroinae_, the first upper incisor is narrow, curved, and much exceeds the others in length; the upper canines are persistent, flattened, blunt and slightly curved, and the first two premolars of both jaws have large, simple, compressed crowns, with a nearly straight or slightly concave free cutting-edge, and both outer and inner surfaces usually marked by a series of parallel, vertical grooves and ridges. Molars with quadrate crowns and a blunt conical cusp at each corner, the last notably smaller than the rest, sometimes rudimentary or absent. Forefeet narrow; the three middle toes considerably exceeding the first and fifth in length and their claws long, compressed and but slightly curved. Hind-feet as in _Macropus_. Tail long, and sometimes partially prehensile when it is used for carrying bundles of grass with which these animals build their nests. The group is confined to Australia and Tasmania, and all the species are relatively small.