200 



NATURAL HISTORY. 



None of the animals hitherto desci'ibed as Kangaroos have any prehensile power in the tail ; but 

 in one group of the Kangaroo-Rats, the tip of the tail has a brush of long hairs above, and is clothed 

 beneath with short hairs, which are closely applied to the skin. This structure, and the motion 

 of the muscles beneath, give the Tufted-tailed Kangaroo-Rat* of New South "Wales a power of 

 encircling and holding objects, especially for seizing grasses with which to make its nest. This is 

 placed in a hollow in the ground, excavated for its reception, and its opening being on a level 

 with the surrounding herbage, the practised eye of the native is required to discern it. After the little 

 things creep in, they drag some grass after them, and close up the place. In the evening, they sally 

 forth and scratch and dig up roots with their strong fore-claws. 



B 



THE SAT-TAILED HYPSIPRYMNUS.f 



The Rat-tailed Kangaroo-Rat is about fifteen inches and a half long, and the tail measures, in 

 addition, more than nine inches. It has a long head and rather short hind feet, and the rat-like tail 



has short stiff hairs on it which do not quite hide the scaly skin beneath. 

 The body fur is long and loose, and dusky brown, more or less tinted 

 with black and pale yellowish-brown. The end of the nose or muzzle 

 is spotted, and the ears are short and rounded. This little animal lives 

 in New South Wales, and was that which was first described by Hunter 

 under the name of Potoroo, or Poto Roo, being the " Bettong " of the 

 natives of New South Wales. The stomach of the Kangaroo-Rats is 

 less sacculated than that of the Kangaroos, but its left-hand portion 

 is enormously developed in proportion to the rest, and may be compared 

 with that of the Ruminantia in point of relative size. It may be noticed 

 that the lower jaws of the Potoroos, which are largely inflected at the 

 angle, articulate with the skull rather differently to those of the 

 Kangaroos. In these last, the cavity at the base of the zygomatic 

 process which receives the lower jaw is broad and slightly convex, 

 permitting considerable side-to-side movement which is useful in the 

 occasional "cud chewing." But in the others the cavity barely deserves 

 the name, it being a nearly flat surface, and, therefore, not much 

 motion, except that of an up-and-down kind, is possible to the jaw. 

 The organ of hearing has been slightly noticed in the Great Kangaroo 

 in a former page, and it is necessary to observe that the tympanic bone 

 does not form a perfect tube in the Potoroos as in the Kangaroos, and 

 that the surface of the auditory cavity is also increased by a " bulla," 

 or bony cavity, bulging out at the under part of the skull. Corre- 

 sponding " bullse " were noticed in the Rodentia, but in their case the 

 swelling is in the temporal bone, whilst in the Marsupials, with the 

 exception of the Wombat, they are formed out of the sphenoid bone (the 

 great ala). Moreover, the Potoroos, like the Kangaroos, and some of 

 the other Marsupials (the Ph.alangers and Koalas), have the ear 

 chamber prolonged, by a number of cells, into the zygomatic process of 

 the temporal bone. The Kangaroo-Rats are numerous, and there are 



many species. They are distributed in New South Wales, Western Australia, Yan Diemen's Land, 

 and South Australia, and to the north-east. 



Sir R. Owen investigated the anatomy of a small Kangaroo-Rat which had been described by 

 Mr. Ramsay in Australia, and which was remarkable for its musky smell. It is a long and slender- 

 bodied little animal, measuring about one foot three inches and a half from the snout to the end of the 

 tail, which is five inches and nine lines in the female, and rather less in the male. Its hinder legs are 

 shorter, and the head is more slender and pointed than in the Kangaroo-Rats just described. The 

 fur is of moderate length, pretty closely applied, and has numerous rather long hairs scattered here 



* Hypsiprymnus penicillatus. f Hypsiprymnus murinus. 



FORE (A) AND HIND (B) FOOT 

 OF HYPSIPRYMNUS. 



