IIOIIN EXPEDITION— MAMMALIA. 
13 
The second specimen is that of an “ adult” animal from Ayers Rock. The 
fourth molar in each jaw is not yet completely cut through. In the upper jaw the 
space between the roots of on each side is 5 mm. The enamel-covered part of 
i'^ is 9 mm. high and 5 mm. broad. The antero-posterior dimension of is 9'5 
mm. There is a fairly well-mai’ked single groove. There are no central connecting 
ridges to the antei’ior transverse ridges of the molars. 
The anterior palatal foramina measure 13 mm. in length, reaching well back 
to the suture between the maxilhe and preniaxilhe. The greatest length of the 
nasals is 70 mm.; least combined width (in middle), 15 mm.; greatest combined 
width (at the posterior end), 31‘25 mm. 
The colour markings of the animal agree with those of AI. rufus, to which the 
animal may be undoubtedly referred. The molar teeth, as seen in the “ adult ” 
specimen are those characteristic of the species, with which they also agree in the 
length of the anterior palatal foramina. is longer than the same tooth in the 
typical M. rttfus, and more resembles that of AI. giganteus, though in the presence 
of only one notch it still more closely resembles that described in AT. antilopinus. 
The most important ditierence which they show when compared with the 
typical skull dimensions, as given by Mr. Thomas, is in regard to the nasals. 
In AI. rufus these are described as “ very long, narrow, parallel-sided, their 
middle width going from 4 to 4i- times into their length.” In AI. giganteus the 
nasals are described as “ broadening behind.” The dimensions given above show 
that the relation between the least width and the length of the nasals is tliat given 
by Mr. Thomas, but that there is a most marked broadening behind, and, further, 
that there is a great dilierence in this respect between the two specimens. In the 
second the posterior is more than twice the median width. 
Evidently there are, as shown in the case of 7®, the anterior palatal foramina 
and the nasals considerable variations to be found within the limits of the species, 
and it may not be at all unlikely that such forms as AI. antilopinus., AI. isabeltinus, 
and AI. niagnus will turn out to be simply varieties of the form AI. rufus, which is 
widely distributed through the central parts of the continent. 
Habitat .—The inland parts of New South Wales and South Australia, and 
the whole central area from the south of Lake Amadeus to the Burt Plains north 
of the McDonnell Ranges. As stated above, there can be no doubt but that its 
range extends across the desert into West Australia. 
