PROFESSOE OWEN OX THE FOSSIL MAMMALS OF AUSTRALIA. 



191 



trary, to impose their own specific denominations on the so demonstrated distinct kind 

 of Wombat. 



^ 13. Mandibular fossils o/' Phascolomys latifrons. — Of six other mandibular frag- 

 ments showing the fore part of the ectocrotaphyte depression, two mutilated right rami 

 (Plate XXII. figs. 4 & 5), by the gradual beginning and degree of deepening of that 

 depression (/), agree with the perforate or normal mandible of Phascolomys latifrons. 

 The outer orifice of the transverse canal or perforation (ib. ^) holds the same position 

 in these fossils : one of them (ib. fig. 4) includes the four anterior molars and the socket 

 of the fifth ; the other (fig. 5) includes the four posterior molars. The fore-and-aft 

 extent of the series of five sockets, in each specimen, is 2 inches, the depth of the man- 

 dible at the back part of the symphysis is (in fig. 5) Q\ lines ; in fig-. 4 it is 1 inch 5 

 lines. The ectalveolar groove (Plate XIX. fig. 4, u) is narrow. The inner wall of the 

 ramus, forming that of the second [cl 3) and third {d *) sockets, descends more vertically than 

 in the fii'st described fragment (Plate XX. fig. 2), or in the Tasmanian (Plate XIX. fig. 1) 

 and Platyrhine (ib. fig. 2) Wombats. The hind end of the symphysis is on the vertical 

 parallel of the interval between d 4 and m 1, or not further back than the middle of m 2 

 (Plate XIX. fig. 4, s'). In both these characters the present fossils come nearer to the 

 latifront species (Plate XX. fig. 1, s) than to the Platyrhine and Tasmanian Wombats. 

 The first molar [d 3) repeats the formal characters of that tooth in the Phase, latifrons. 



I conclude, therefore, that the mandibular fossils under description belonged to a 

 "hairy-nosed" Wombat, and one nearer to the existing species than the preceding fossil 

 (Plate XX. fig. 2), in which the symphysis appears to have extended as far back as it 

 does in Phascolomys ])lattjrMnus (Plate XIX. fig. 2). 



§ 14. Mandibular fossils of Phascolomys Mitchelli. — I now come to mandibular 

 fossils which, in the depth of the base of the ectocrotaphyte depression (Plate XXI. 

 fig. 5,y), resemble the Tasmanian and Platyrhine Wombats. Four of these have the 

 entire molar series in place. In one (Plate XIX, fig. 5) the extent of the series is 2 

 inches 2 lines ; the first molar, however (d 3), agrees in shape and size with that in Phase, 

 latifrons (Plate XX. fig. 1, d 3). 



The transverse concavity of the inner wall, continued from the first and second molar 

 sockets and upon the symphysis half an inch in advance, more resembles that in the im- 

 perforate variety of the Latifront Wombat than in any other mandible of recent species. 

 The symphysis (Plate XXI. fig. 6, s) does not extend so far back as in the Tasmanian 

 (ib. fig. 1, s) and Platyrhine (ib. fig. 2, s) Wombats. From the fore part of the first 

 molar socket to the back part of the upper division (ib. fig. G, s*) of the symphysial 

 surface, in the fossil, measures 1 inch ; and this part of the symphysis is on the vertical 

 parallel of the hind lobe of the second molar. The lower division (s) terminates, as in 

 fig. 4, below the interval between d* & mi. 



The fore part of the root of the coronoid, in the fossil (ib. fig. 5, q), stands out from 

 the alveolar wall of the penultimate molar, as in Phase, latifrons ; not from that of the 

 last molar, as is the rule in the Tasmanian (Plate XXII. fig. 1, q) and Platyrhine (ib. fig. 



2 c 2 



