PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
183 
Queensland . — In a heavy petrified fragment of skull (Plate XVIII. figs. 1-4) f, including 
the molary series, upper jaw, and their alveoli, with the bony palate from its hind border 
or bar ( a ) to 4 lines in advance of the molars ( 21 , 21 ), the palate, as compared with that 
of the last-described fossil (Plate XVII. fig. 5), is more concave transversely, and its 
concavity is divided by a sharp ridge, extending from the interpalatine ( 20 , 20 ) along the 
intermaxillary J palatal suture, as far forward as the second molar ( d 4 ). 
The upper molars have a somewhat zigzag arrangement : the second (Plate XVIII. 
fig. 1 , d 4 ) extends more mesiad than the first (^ 3 ) or the third (m 1 ), the hind lobe of 
the third more so than the fore lobe of the fourth (m 2 ), and the hind lobe of the fourth 
more so than the fore lobe of the last molar (m 3). This arrangement is also shown in 
the palatal view of the fossil of Phascolomys Mitchelli (Plate XVII. fig. 5), and by the 
alveoli in the more fragmentary fossil of the same species (fig. 8) of the same Plate. 
The same character is seen in a minor degree in the outer contour of the grinding- 
surfaces. The antero-external angle of one tooth projects more outwardly than the 
postero-external angle of the tooth in advance. This arrangement, a tendency to which 
has been noted in Diprotodon and Nototherium , is more marked in the Tasmanian and 
Platyrhine Wombats, as in Mitchell’s fossil, than in Phascolomys latifrons. 
The intermolary bony palate in the present fossil (Plate XVIII. fig. 1), though 
exceeding in length by the antero-posterior diameter of the last molar tooth that of 
Phascolomys latifrons (Woodcut, fig. 8), is narrower anteriorly than in that species, 
without being so broad posteriorly. It further differs from both this, the Platyrhine 
(Woodcut, fig. 7) and the Tasmanian existing Wombats, in the smaller size of the post- 
palatal foramina (ib. h, h ) ; they are absolutely smaller than in Phascolomys vombatus , 
although the fossil indicates an animal as large as the largest Phascolomys platyrhinus. 
These foramina are, unfortunately, not preserved in the two previously described fossils ; 
but the anterior boundaries in the subject of fig. 5, Plate XVII. indicate a size or breadth 
of the foramina equal to those in either the Latifront or Platyrhine existing species. 
The antero-posterior extent of the molary alveoli, upper jaw, of the present fossil is 
2 inches lines, which is exactly that in the cave-fossil (Plate XVII. fig. 5) and in the 
largest Platyrhine Wombat. But the palate is narrower in the fossil by 1 line posteriorly, 
besides being deeper or more concave across, and divided by a mid ridge. 
The differential character noticed in the preceding fossils is here repeated, viz. the 
grealer depth of the outer alveolar plate of the maxillary (Plate XVIII. fig. 2, 21 ) below 
the zygomatic process (ib. 21 *); it is 10^ lines in the present fossil, and the premas- 
seteric ridge or tuberosity (ib. m), less defined or prominent than in existing Wombats, 
is correspondingly raised above the alveolar outlets. 
The worn surfaces of the molar teeth are rather broader transversely than in Phasco 
t This fossil was presented to the British Museum, in 1861, by George Bennett, Esq., F.L.S. It is from a 
freshwater deposit, Darling Downs. 
+ I use the term to signify the suture between the maxillary bones, in a sense different from that in whicl 
it is sometimes applied, viz. to the “ premaxillary bone.” 
2 b 2 
