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2 inches 2\ lines, which is exactly that in the cave-fossil (Plate L. 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 

 greater depth of the outer alveolar plate of the maxillary (Plate LI. 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- 

 lomys platyrhinus, and the inner ends of the two lobes are more sharply, or less obtusely, 

 angular than is usual in that species. The difference both in this character and the 

 breadth of the molars is also notable between the present and the first-described fossil ; 

 but seeing the influence direction and degree of attrition have upon the size and shape 

 of the grinding-surface of the molars, the differences noted may be within the limits of 

 that influence. In the subject of Woodcut, fig. 7, d 4 had been abnormally abraded. 



The characteristic downbending of the hind part of the palatines, which forms a trans- 

 verse bar (Plate LI. fig. 1, a) behind the postpalatal apertures (ib. b, perforated at 

 each end from behind forwards by a smaller aperture in the recent Wombats, is repeated 

 in this present instructive fossil (ib. fig. 4, d, d). 



This evidence of Phascolomys Mitclielli (Plate LI. figs. 1-4), from freshwater 

 deposits, resembles Phase, platyrhinus in the depth and position of the antero-internal 

 longitudinal groove of d 3, which tooth is wanting in the cave fossil, although the socket 

 (ib. fig. 5, d 3) indicates the same position of the groove. In Phascolomys latifrons the 

 fore part of d 3 (Woodcut, fig. 8) is less produced than in Phase, platyrhinus and Phase. 

 Mitchelli. 



A difference in the grinding-surface of the upper molars and in the intervening bony 

 palate between the subjects of fig. 5, Plate L., and fig. 1, Plate LI. is appreciable; 

 but, as above remarked, the one may be due to a phase of attrition ; and, moreover, the 

 outer side of the surface is slightly mutilated in fig. 5, Plate LI. ; whilst the variety 

 in regard to a rising along the mid palatal suture in the Platyrhine Wombats warns 

 against founding a specific distinction thereon. 



These characters are of the less consequence, since, where they are not preserved in a 

 fossil, there may be others which allow of no such hesitation in regard to the specific 

 distinction of the Wombats ; as, e. g., in the case of that to which the fragment of skull 

 about to be described belongs (Plate LI. figs. 5, 6, 7). It is a portion of the left 

 maxillary with the bony palate intervening between the left and right molary series, the 

 left series being in place (ib. fig. 7), the right represented by the second molar and the 

 alveoli of the two following teeth : the extent of the left molary series at their issue 

 from the alveoli is 2 inches 2 lines. 



The chief value of the present specimen is the character of the malar process of the 

 maxillary (ib. fig. 5, 21), which is preserved with the beginning of the attached part of 



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