A DESCRIPTION OF MACROPUS ISABELLIMTS, GOULD — WAITE. 133 



the average length ; the molar series are parallel ; the anterior 

 pair have passed out of action, are deflected downwards, much 

 produced forwards, and blackened by disuse. 



Dimensions of Skull. mm. 



Basal length 144-0 



Greatest breadth 90-0 



Nasals, length ... ... ... ... 59-0 



„ breadth ... ... ... ... 23-3 



,, central breadth ... ... ... 19*2 



Constriction ... ... ... ... 14'3 



Palate, length 93-0 



„ outside M"^... ... ... ... 46-5 



inside M- 28-3 



Palatal foramina ... ... ... ... 105 



Diastema ... ... ... ... ... 38'3 



Basi-cranial axis ... ... ... ... 42 '5 



Basi-facial axis ... ... ... ... 105*0 



Facial Index 247 



Teeth,Mength of I^ 8-4 



Teeth, length of J/.^'- 26-5 



The aggregate characters of this animal indicate what may be 

 its habit in life. A stunted kangaroo, inhabiting a bleak island, 

 it is of stout and heavy build, ill adapted to life on the plains, 

 but well fitted for rough country : this may be adduced from 

 its stout short limbs, the hind ones especially, and the thick, long 

 hair of the feet entirely concealing the claws, as in the typical 

 rock wallabies (Petrogale) and, in a lesser degree, the wallaroo 

 {M. robustus) of the mountains. Its characters are so marked 

 that it fails to satisfy the conditions of Mr. Thomas' synopsis, ^ 

 for, while the size of its skull well admits it as a kangaroo, the 

 shortness of its hind feet classes it as a wallaby. The skull also is 

 peculiar, and exhibits a higher cranial index than any other 

 kangaroo. In some of the wallabies, however, the cranial index 

 is much higher than in M. isabellinus. 



All the previously published descriptions of this species are 

 based upon the type specimen in the British Museum ; this 

 " consists merely of a flat skin, without head, arms below elbows, 

 legs, or tip of tail." 



From such imperfect material Thomas ventured the opinion 

 that it is most nearly allied to M. rufus. In colour and the 

 general appearance of the fur this is so, but when taken in its 

 entirety it is more akin to M. robustus. Judging from our single 



3 In the British Museum Catalogue, loc. cit., p. 29, 13 is misprinted 

 I*, and apparently also on p. 13 in connection with M. magnus. 

 * Thomas — Loc. cit., pp. 11, et. seq. 



