1897.] FROM IfOETH AUSTRALIA. 325 



68 mm. P^ and the milk p* are fully developed ; 'm} is just 

 emerging from the alveolus. 



Middle stage. Two skulls, length 121 mm. and 126 mm., are just 

 in the stnge when p^ and the milk p* are at the point of being 

 changed. In both specimens the persistent p* is already developed 

 in one of the upper jaws ; in the other jaw p^ and the milk p* are 

 still present, but the persistent p"^ is (in the largest specimen) 

 visible above their roots through a bole in the maxillary. In the 

 lower jaw on one side, too, the persistent jj'* is developed, on the 

 other side not. 



Adult stage. Two full-grown specimens, having the following 

 sizes : — 



Male : length 152, breadth 80 mm. 

 Female: „ 140, „ 74 „ 



Two other skulls belong, too, to old specimens ', but are smaller, 

 their length being 129-136 mm. 



In all these four skulls mi' is fully developed ; a line between the 

 tips of z)^gomatic processes wOl touch the middle (or in the old 

 male the posterior part) of m\ 



Between the middle stage and the adult there are nine skulls 

 (length from 119 mm. to 146 mm.), none of which have wi^ f"lly 

 developed. The line between the tips of zygomatic arches will 

 touch the middle of m^, in the youngest specimens the posterior 

 part of m'. 



Between the middle stage and the young one there are four skulls 

 (length between 118 mm. and 123 mm.). P^ and the mUkp* are 

 still present ; m^ is only half-developed. 



Hah. The commonest species in Arnhem Land and at Eoebuck 

 Bay, and met with everywhere along the great rivers ; especially 

 numerous in the big bamboo-jungles. 



Native names : Ma, Bulak. 



17. Maceoptjs eobustus (Gould), 1840. 



Macrojms robustus, Thos. Cat. Mars. Monotr. Brit. Mus. p. 22 

 (1888); Ogilby, Cat. Austral. Mamm. p. 58 (1892). 



N. Australia : South Alligator Eiver, June 17th, 1895 (one 

 specimen, a female, with a young one from its pouch). 



Skull. Length of the skull (female) 139 ram., breadth 77 mm. 

 The last molar has not yet reached its full height. 



Ifab. In the central tablelands, Arnhem Land, scarce, solitary. 



Native name : Tjikurr (male) ; Tjugeri (female). 



18. Peteogaib concinna, Gould, 1842. 



Petrogale concinna, Thos. Cat. Mars. Monotr. Brit. Mus. p. 71 

 (1888); Ogilby, Cat. Austral. Mamm. p. 48 (1892). 



N. Australia: Daly River, July 21 st, 1894 (one specimen). 

 Mary Eiver, May 1895 (seven specimens and two embryos). 



SMn. In all specimens the white tips of the hairs on the back 



' Sex undetermined, but probably both females. 



