Tertiary.] PALEONTOLOGY OF VICTORIA. [Mammalia. 



P. platyrhinua. The diastema is narrower between the molars in 

 this fossil than in the recent species ; and the portion in front of 

 the anterior molar (D ") is so much shorter in the fossil that it seems 

 thicker or deeper, and the lower outline of the mandible rounded 

 with a more uniform cm-ve, than iu the recent species, although the 

 depth below the molar series is nearly alike in both. The anterior 

 outlet of the dental canal is closer to the anterior molar than in 

 P. platyrlnnus^ and the incisors are more compressed, or not nearly 

 so wide in proportion to the tlnckness as iu the living species, 

 their vertical and transverse diameters being almost equal. 



Of fossil species it is only closely related to the P. Mitchelli 

 (Ow.), from the Wellington caves in New South Wales, l)ut it differs 

 in its much larger molars, and in the symphysis extending behind 

 the third molar instead of only behind the second, as in P. Mitchelli. 



This is the first fossil ever found, as far as I know, in our 

 Victorian gold drifts, the specimen figured on Plates III. and IV. 

 having been cut out of the hard ferruginous gold cement of 

 Dunolly. It is one of the important specimens we owe to my 

 friend, Mr. J. A. Pauton, Warden of Bendigo at the time of its 

 discovery, and is of great interest as thus showing that our gold 

 (h'ifts are not " alluvial," but of the more ancient Pliocene Tertiary 

 period, at least as old as the Mammaliferous Crag ; thus correspond- 

 ing in age with the gold drifts of the Ural. The species occurs 

 also commonly in various supei-ficial localities in clays, with the 

 Macropus Tifa7i., and M. Atlas and other extinct forms. 



Explanation op Figdres. 



Plate III. — Figure of mandible embedded in the hard gold cement of Dunolly riewed from 

 above, natmal size. 



Plate IV. — Fig. 1, same specimen viewed from the side. Fig. la, view of condyle. 



Plate V. — Fig. 1, portion of lower jaw viewed from above, natural size, showing symphysis 

 complete at the back, but imperfect in front, and the whole of the molar series complete. 

 From the shores of Lake Bullcn-merri, near Camperdown. Fig. la, transverse section of 

 incisors showing the compression. Fig. 2, same view of another specimen, showing the 

 symphysis complete from the posterior to the anterior margin, but wanting the last molar 

 and condyle, natural size. Fig. 2a, transverse section of incisors showing the compression 

 or great vertical diameter of each. Fig. 26, side view of same specimen, showing the 

 form of the under contour of the jaw, and the position of the ectacrotaphite cavity. 

 Fig. 3, outhne of corresponding part of the living Phascolomi/s plati/rhinus, showing the 

 more backward place of the anterior molars, natural size. Fig. 3a, transverse section of 

 incisors, showing their greater comparative lateral extension. Fig. 34, outhne lateral view of 

 same specimen to contrast with fig. 2A in the more backward position of the anterior connuence- 

 ment of the molar series, and the more slender form of the jaw between them and the incisors. 



FuEDERicK McCoy. 



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