The anatomy of this genus has been described by Owen for _D. inustus_,[83] and by myself for _D. bennetti_. The stomach, which {137} has a single, not bifid, cul-de-sac, is sacculated by two principal bands and other subsidiary ones. Its internal structure has already been to some extent described. The spleen of _D. bennetti_ is remarkable for the fact that it is not [84]-shaped, whereas _D. inustus_ agrees with other Macropodines in the form of this organ. The small intestine of _D. bennetti_ is 95 inches long, the large 38. The caecum appears to differ in the two species; it is smaller in _D. bennetti_, where it is only 2 inches in length. The most remarkable feature of the liver is the large size of the left lateral lobe and the bilobed condition of the Spigelian lobe; this at least was the case with _D. bennetti_. A recently-described species[85] has been attentively studied in its native haunts by Dr. Lumholtz.[86] It lives in the highest parts of the mountainous scrubs of Queensland, where it moves quickly on the ground as well as among the trees. It is hunted with Dingos by the "blacks," and is eaten by them.[87] _Lagostrophus_ is a generic name that has been proposed by Mr. Thomas for a small Wallaby 18 inches in length, which is distinguished by the fact that the long claws of the hind-limbs are entirely hidden by long and bristly hairs; the muffle is naked; there is no canine. The bullae are swollen. There is but one species of the genus, _L. fasciatus_, a native of West Australia. SUB-FAM. 2. POTOROINAE.--_Aepyprymnus_ and the other genera placed in this sub-family are known by the vernacular name of Rat-Kangaroos, or sometimes Kangaroo-Rats. The latter term has been called "incorrect," though it is just as good as the former, both of them in fact being inaccurate as implying some likeness to or relation with a Rat. The present genus has a partially hairy rhinarium; the auditory bullae are not swollen. It contains but one species, _Ae. rufescens_, a native of Eastern Australia, which is distinguished by its very long hind-feet. _Bettongia_ has long hind-feet as in _Aepyprymnus_, but the rhinarium is entirely naked instead of being partially hairy, while the ears are much shorter. The genus, which contains four species, is remarkable as being the only ground-living mammal with a prehensile tail, which it uses to carry grass, etc. {138} _B. lesueuri_ burrows in the ground, often to so great a depth as 10 feet. The genus occurs in Tasmania as well as in Australia. _Caloprymnus_, with one species, is a genus instituted by Mr. Thomas in his Catalogue of Marsupials for a form (_C. campestris_) which combines in a remarkable way the characters of _Aepyprymnus_, _Bettongia_, and _Potorous_. The external characters and the general shape of the skull are as in _Bettongia_, while the molars have the structure of those of _Aepyprymnus_. The last premolar is as in _Potorous_.