317 



of the whole lateral margin of the bone. The basal breadth bears almost the same 

 proportion to the length of the nasals as in the first cited skull. 



§ 3. Nasal bones in Phascolomys platyrhinus, Ow. — The Platyrhine Wombat, in the 

 absence of postorbital processes, the shortness of the naso-maxillary suture, and the 

 deep emargination of the fore part of the nasal process of the premaxillary, is more 

 nearly allied to Phase, vombatus than either of these species are to Phase, latifrons ; but 

 the nasal bones (fig. 3, is) are relatively broader in the Platyrhine than the Tasmanian 

 Wombat, the outer basal angles approaching as near to the lacrymal tubercles (ib. 73) 

 with a greater relative breadth of the skull at that part. In one skull the lateral 

 borders of the nasals have the same undulatory course, but more feebly marked than in 

 the second variety of Phase, vombatus (fig. 1). In a second the suture between the 

 nasals (is) and premaxillaries (22) runs as in fig. 3. There is a narrow and irregular 

 intrusion of the frontal at the middle of the fronto-nasal suture, sometimes at the 

 expense of the right (as in fig. 3), sometimes of the left nasal bone. The breadth of 

 the base of both bones equals five sevenths of the length of the nasals in two specimens, 

 and four fifths in a third. The apices (is), projecting anterior to the naso-premaxillary 

 suture (22'), are blunter than in the first variety of Phascolomys vombatus. The width 

 or breadth of the nasals, at their base or fronto-nasal suture, begins to diminish at once, 

 as they advance, by the converging course of the naso-maxillary (15-21) and naso-pre- 

 maxillary (15-22) sutures. In not any of the three specimens before me is " the width of 

 the nasals continued forward beyond their middles" *. In one variety the course of the 

 naso-premaxillary suture was such as is shown by the dotted line a a in figure 3. A 

 broader strip of the maxillary (21) divides the malar (26) from the premaxillary (22) in the 

 present species than in Phascolomys vombatus. This is a good and constant character 

 in a comparison of the two species. 



§ 4. Nasal bones in Phascolomys latifrons, Ow. — The breadth of the fore part of the 

 frontals in the Latifront or Hairy-nosed Wombat is made to contrast with the narrowness 

 of the rest of the bones by the outward extension of the postorbital processes; the 

 nasals (fig. 4, 15) present a more regular triangular form, through the prevailing trans- 

 verse course of the fronto-nasal suture (n-is) and the more regular convergence of the 

 lateral margins of the nasals to the fore ends of the naso-premaxillary sutures (15-22). 

 Beyond these the lateral margins of the nasals converge more rapidly to their apices (15'), 

 which extend freely further forward than in the two preceding species. The breadth of 

 the nasals at the base of their free extremities is greater than in the bare-nosed Wom- 

 bats, and the upper surface of the entire bones is flatter. 



In one of the two skulls before me of Phascolomys latifrons the left frontal breaks 

 the transverse course of the fronto-nasal suture by a sharp-pointed process or wedge 

 between the two nasals (indicated by the upper line in fig. 4); in the second skull 

 the right frontal sends forward in the same way a more obtuse triangular process; in 

 my type skull (Zool. Trans, vol. iii. pi. xxxvii. fig. 4) both frontals contribute equal 



* Mueie, Proc. Zool. Soc. p. 803 (1367). 



29* 



