PETROGALE XANTHOPUS, Gray. Yellow-footed Rock Wallaby. Petrogale wanthopus, Gray in Proc. of Zool. Soc., Nov. 14, 1854. Aut that is known respecting this fine animal is, that two examples, a male and a female, were collected on Flinders’ Range in South Australia, and sent to this country by Mr. Strange, and that they were subse- quently purchased by Dr. Gray for the British Museum collection, wherein they are now deposited. The Petrogale wvanthopus is a typical example of the genus to which it belongs, and may be regarded as one of the finest species of the form yet discovered. Its large size and rich colouring render it very conspicuous, while the buffy hue of the ears and legs at once distinguishes it from the whole of its congeners. The habits, actions and economy of the Petrogale xanthopus are doubtless as similar to those of the other members of the genus as it is like them in form, but on these points nothing is at present known. Fur long, soft, and yieldmg to the touch ; face, head, and all the upper surface vinous brown-grey, becoming greyest on the rump; a narrow line of dark rich brown extends from the crown of the head down. the centre of the back; on each cheek a distinct mark of white; eyelashes full, promment, and brownish-black ; behind each arm a large patch of reddish-brown, separated from the general tint of the upper surface by a streak of buffy-white ; ears ochre-yellow, becoming lighter at the pase fringed internally with white, and tipped externally with brown ; front of the arms bright buff; hands mich dams brown ; outer side of the legs light ochreous-brown, fading into white on the inner side, and passing into the rich dark brown of the toes; throat and under surface white; tail ochreous-brown, irregularly barred with a darker tint, and ending in a conspicuous tuft which is rich brown above and SO below. . Of so fine a species I have considered it desirable to give two illustrations,—the entire animal, necessarily much reduced, and a foreshortened figure of the size of life. Nor must I omit to call attention to the interest which would attach to the introduction of living examples to our menageries, and to the acquisition of additional examples for our museums.