PROFESSOR OAVEN OX THE FOSSIL MAM.MALS OF AUSTRALIA. 245 



latifrons (Philosophical Transactions, 1S72, Plate xxir. fig. 3). The anterior part of the 

 origin of the coronoid (Plate XXXIV. fig. 1, q) bears the same relation to the penulti- 

 mate molar, and is more advanced than in Phascolomys platyrhinus. The ectalveolar 

 groove (ib. fig. 3, ii) 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 (/ j, 

 bounded below by the prominent outstanding ridge (A', /«, 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. j)lafyrhimts (ib. fig. 2, s) or Phase, vombatus (ib. fig. 1, s). The 

 upper surface of the symphysis (Plate XXXIV. fig. 3, I) repeats the character of the 

 opposed palatal part of the upper jaw (Plate XXXIL & 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, I, s) 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 W^ombats, but is not so much so as in Phaseolomys Krefftii. The lower 

 contour of the symphysis in Phaseolomys 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 w-all of the ramus and comparative flatness of the 

 postsymphysial inner wall are according to the generic type, and relate to the dii'ection 

 of convexity of the long, bent, deeply implanted, ever-growing molars. 



The first molar [di, 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. In this it difiers from Phascolomys latifrons, Phase. Mitclielli, 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. ])latyrhinus. The 

 fore part of d zva. 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 



