PROFESSOR OWEN ON THE EOSSIL MAMMALS OF AUSTRALIA. 
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latifrons (Philosophical Transactions, 1872, Plate xxn. fig. 3). The anterior part of the 
origin of the coronoicl (Plate XXXIV. fig. 1, q) bears the same relation to the penulti- 
mate molar, and is more advanced than in Ph ascolomys platyrhinus. The ectalveolar 
groove (ib. fig. 3, u) between this process and the last two alveoli is relatively narrower 
than in any of the living species. The fore part of the ectocrotaphyte depression (f j, 
bounded below by the prominent outstanding ridge (If 7i, fig. 1), is less deep than in the 
bare-nosed Wombats, and is more gradually excavated, as in the hairy-nosed species. 
The ramus maintains its depth (1 inch 10 lines) to the socket of the first molar (Plate 
XXXIV. d 3 , figs. 1 & 2). The hind part of the symphysis (ib. fig. 3, s) is on the vertical 
parallel of the hind part of the second molar ( d 4 ), being rather more advanced than in 
Phascolomys latifrons (Philosophical Transactions, 1872, Plate xxi. fig. 3, s), and much 
more so than in Phase, platyrhinus (ib. fig. 2, s) or Phase, vomhatus (ib. fig. 1, 5). The 
upper surface of the symphysis (Plate XXXIV. fig. 3, l) repeats the character of the 
opposed palatal part of the upper jaw (Plate XXXII. & XXXIII. 21 ', 22 ') in its degree of 
transverse concavity ; and this, at the diastemal tract, is bounded by lateral ridges, 
sharper than those above ; they indicate a slightly curved course as they advance, con- 
cave outward, so far as they extend in the fossil. These characters of the upper surface 
of the symphysis are most nearly repeated by Phascolomys Krefftii (Philosophical Trans- 
actions, 1872, Plate xx. fig. 2, l , 5) amongst the smaller Wombats; but in that extinct 
species the symphysis extends back as far as it does in Phase, platyrhinus or Phase, 
vombatus (Philosophical Transactions, 1872, Plate xix. figs. 1 & 2). In Phase, latifrons 
the symphysis is shorter, more concave and more definitely bounded above than in the 
bare-nosed Wombats, but is not so much so as in Phascolomys Krefftii. The lower 
contour of the symphysis in Phascolomys medius rises at a less open angle with the axis 
of the ramus than in Phase, latifrons , and still less so than in the bare-nosed species. 
The lower surface shows the pair of vascular outlets, of small size, 15 lines in advance 
of the hind border. The anterior outlet of the dental canal (Plate XXXIV. fig. 1, v ) 
is relatively rather nearer the socket of d 3 than in the smaller fossil and recent Wombats. 
The vertical convexity of the outer wall of the ramus and comparative flatness of the 
postsymphysial inner wall are according to the generic type, and relate to the direction 
of convexity of the long, bent, deeply implanted, ever-growing molars. 
The first molar ( d 2 , ib. figs. 1, 2, 3) has the usual generic small size and simple form, 
representing, as it were, like its homotype above, one half of the succeeding molars. 
The grinding-surface resembles that of the upper jaw in being suboval, with the long 
axis lengthwise. I 11 this it differs from Phascolomys latifrons , Phase. Mitchelli , and 
Phase. Krefftii , in which that surface is subquadrate, and it resembles, rather, Phasco- 
lomys platyrhinus ; but the larger end of the oval is at the fore part of the tooth in 
Phase, medius , not at the hind part, as is usually seen in Phase, platyrhinus. The 
fore part of d 3 in Phase, medius shows a feeble longitudinal groove, as in Phase, lati- 
frons. The enamel, as usual, coats the outer and fore part of the tooth, but is not 
extended so far from the fore part upon the inner side as in Phase, latifrons. There 
