PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
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does the other two recent species is the greater vertical extent of the maxillary (Plate 
XVII. figs. 3 & 4, 2i*) beneath the origin of the malar or zygomatic process (21*) of that 
bone (compare with Cuts 5 & 6, 21*). I shall recur to this character in the description 
of another fossil of the present genus. 
§ 8. Upper molars 0/ Phascolomys Mitchelli, Ow. — The differential characters of these 
teeth, as compared with their homologues in Phascolomys vomhatus, have been elsewhere 
pointed outf. As to the two larger existing species, in the molar dentition of the upper 
jaw Phascolomys Mitchelli more resembles the platyrhine than the broad-fronted Wombat. 
In the latter the right and left upper molar series (Woodcut, fig. 8 , d z-m 3) run more 
parallel to each other, are less convergent anteriorly, with absolute greater breadth 
of the bony palate there. The first molar (d 3) in Phascolomys latifrons is, relatively to 
the second, larger in both upper and under jaws J. I therefore limit the comparison of 
the upper molars in the present fossil to those of Phascolomys platyrhinus (fig. 7, d 3 -m 3). 
The extent of the five alveoli, lengthwise, taken at their outlets, is the same in both ; 
or at least the fossil (Plate XVII. fig. 5, d *-m 3) exceeds only by about a line, giving 
2 inches 2| lines instead of 2 inches 1 line as in Phascolomys platyrhinus. I have seen 
no example of Phascolomys latif rons in which the molar series extended beyond 2 inches ; 
it is commonly less, as in Woodcut, fig. 8. 
The alveolus of the first molar ( d 3) of the fossil indicates a tooth not larger than in 
the Platyrhine Wombat. The other four molars, of which the first three are preserved 
on the left side and the last two on the right side, closely repeat the characters of these 
teeth in the Platyrhine Wombat §. This gives more weight to the differential characters 
of greater length and less breadth of the nasals, the greater concavity and sharper defi- 
nition of the diastemal part of the bony palate, and the greater depth of the maxillary 
below the anterior pier of the zygomatic arch in Phascolomys Mitchelli. 
§ 9. Palatine foramina in Phascolomys. — I next proceed to notice Phascolomydian 
fossils from the freshwater deposits of Queensland, in the interpretation of which some 
observations must be premised on the palatal foramina in existing species of Wombat. 
In my first paper on the Osteology of the Marsupialia I state that Phascolomys resem- 
bles Phascolarctos and llypsiprymnus in having “ the posterior palatal openings large 
and situated entirely in the palatal bones ; and that posterior and external to these are 
two small perforations” ||. In the other two species ( Phascolomys latifrons and Phasco- 
lomys platyrhinus) determined by cranial characters since the date of that remark (1838), 
the generic characters of the postpalatal openings are repeated. These additional mate- 
rials serve to test the statement that in Marsupials “ the perforations of the bony palate 
f Mitchell’s * Three Expeditions into the Interior of Eastern Australia,’ vol. ii. p. 3G8, pi. 4S. See also 
Waterhouse, ‘ Natural History of the Mammalia,’ 8vo, 1845, p. 244. 
t Loc. cit. p. 304. 
§ The second molar is abnormally worn, through slight displacement of the opposing tooth, as happens in 
other partially enamelled teeth of perpetual growth. 
|| “ On the Osteology of the Marsupialia,” Trans. Zool. Soc. vol. ii. p. 389. 
MDCCCLXXIl. 2 B 
