415 



which the state of petrifaction of the lacustrine fossils made more difficult than in the 

 Cave specimen. The fore link is a little more marked in ni2 than in the type speci- 

 men, but the agreement in other characters is sufficiently close to determine the species 

 and subgenus as above defined. 



The next Bennettian specimen is from a somewhat older individual of Phascolagus 

 altus ; it is a portion of the right maxilla with d i, m 1, and m 2 in place ; these three 

 molars occupy the same extent as that in the skull of Boriogale magnus, the upper 

 molars of which are figured in Plate LXXX. fig. 12 — an extent about 1 line short of that 

 in Macropus rufus (Plate LXXXIII. fig. 1), and about 1 line more than that in Osphranter 

 robustus (fig. 3, Plate LXXXI.). We have here, therefore, plainly demonstrated, the 

 representative of a Kangaroo about the size of the largest now living in Australia. Inde- 

 pendently of the premolar character shown in the previous specimens, the present fossil 

 could not be referred to Macropus major. The antorbital foramen is too remote from 

 the orbit and from the ridged beginning of the masseteric process, which also is more 

 directly continued from the fore border of the orbit than it is in Macropms major. 

 The foramen in question is 7 lines in advance of the nearest part of the masseteric ridge 

 in the fossil ; it is 3^ lines in advance of that ridge in Macropms major. 



In the position of the antorbital foramen the fossil more resembles Osphranter 

 robustus, in which, however, the foramen is about a line further in advance of the 

 masseteric ridge ; this, in its prominence, sharpness, and the depression anterior to it, 

 resembles more than does Macropus major the fossil fragment compared. Boriogale 

 more closely repeats the above-defined cranial character in the fossil. But Phascolagus 

 has the palate entire, where Boriogale shows the large vacuity (Plate LXXX. fig. 12) 

 common to it with the type species of Halmaturus, F. Cuv. In the molars of Phasco- 

 lagus the prebasal ridge is larger than in Boriogale ; the breadth of the outer sides of the 

 two main lobes is greater ; the postbasal ridge better defines the hinder depression below. 



Both the cranial and dental characters of Phascolagus forbid its reference to a Boriogale. 

 In the upper molars of Osphranter, with a prebasal ridge developed in the same degree 

 as in Phascolagus, the fore link is also present, though feeble ; yet in a more conspicuous 

 degree than in Phascolagus, where it can hardly be said to exist : the fore link is better 

 developed in the upper molars of Macropus major, and the valley is wider between the 

 two lobes. 



The remains of the alveolar cavities for the two roots of the premolar show that it 

 had come into place in the fossil under review ; and the fore-and-aft extent which the 

 two cavities occupy with the width of the intervening tract of bone indicate a premolar 

 about the size, in that dimension, of that of the type specimen (Plate LXXXII. fig. l,p 3), 

 and rather longer than the following tooth (d 1), but far short of the proportions which 

 characterize p 3 in the genera Sthenurus and Protemnodon, next to be defined. The 

 state of the socket of m 3 in the Bennettian specimen, and the rising of its base between the 

 insertions of the fore and hind fangs, clearly bespeak that this tooth had likewise 

 come into place, and that the fossil under comparison is from a nearly mature indi- 



42* 



