182 



PEOFESSOE OWEN ON THE FOSSIL MAMMALS OF AUSTEALIA, 



deserve particular attention ; they are generally specific, and of consequence in the deter- 

 mination of recent and fossil species''^. 



In the skull of the Wombat from Tasmania [Phase, vombatus), figured in the same 

 Paper J to illustrate the palatal and other characters afforded by a basal view of the 

 cranium, the foramina are oval, the base Avhich is behind being rounded ; but the small 

 anterior end of the oval is so nearly pointed as to suggest the term " triangular." In 

 two skulls since compared these foramina present the same shape and proportions ; in two 

 smaller and younger skulls of Phase, vombatus they are relatively smaller, and rather 

 elliptical than oval. In two skulls oi Phascolomys ylatyrliinus in the Collection of the 

 British Museum I note that the postpalatal foramina are longitudinally elliptical or 

 oblong in one, and are triangular in the other ; the larger continental bare-nosed species 

 showing the same variety as the smaller Tasmanian Wombat. This, therefore, is an 

 exception to the general rule of the specific value of the postpalatal character §. The 

 larger, especially the longer postpalatal varieties, encroach more forward and come 

 nearer to the transverse parallel of the anterior wall of the hindmost socket. Allowance 

 must be made for this variation. 



In two skulls of Pha^eolomys latifrons the postpalatine foramina are relatively larger, 

 especially longer, than in either the Tasmanian or Platyrhine Wombats, and they ar6 

 rounded anteriorly, but less broad there than behind. 



Dr. MuRiE II notes the larger size of the postpalatine foramina in Phase, latifrons as 

 compared with Phase, plafyrhinus, and I therefore attach the more value to the cha- 

 racter, as probably being more constant in the latifront species. It must, however, be 

 considered in connexion with the more constant cranial characters. The following 

 fragmentary fossil from the " breccia-cave " of Wellington Valley exemplifies the need of 

 keeping this relation in view. The fossil consists of a left maxillary and palatine, with 

 the molar alveoli, fractured at both ends (Plate XVII. figs. 7, 8) ; the anterior fracture 

 exposes the socket of the first molar, d s. By the anterior contraction of the palate and 

 by the size and proportions of the alveoli the fossil resembles Phascolomys platyrhinus ; 

 by the parallelism transverely of the fore part of the postpalatal aperture and the same 

 part of the posterior alveolus, and by the height of the maxillary below the malar process 

 of that bone (fig. 7, it resembles Phascolomys latifrons. By the combination of both 

 characters it proves its relationship to Phaseolomys Mitehelli ; as in that species the prczy- 

 gomatic ridge is less prominent or definite, and is higher placed than in existing Wombats. 



§ 10. Palate and upper molars., Phascolomys Mitehelli, from freshwater deposits, 



t " On the Osteology of the Marsupialia," Trans. ZooL Soc. voL ii. p. 388. 

 X lb. plate L\.xi. fig. 0. 



§ The skull of the Wombat, from New South Wales, vith "two large triangular holes in the end of the 

 palate," was probably the only one in the British Museum Collection at the date of Dr. Gray's eomparison 

 of it with the smaller Tasmanian species, which ho believed to be differentiated by the " two moderate-sized 

 oblong holes in the hinder part of the palate." (" Some Observations on the skull of rhascolomys vombatus," 

 by J. E. (iiiAY, F.R.S., I'roc. Zool. Soc. 1847, p. 41.) 



II Loc. cit. p. 844. 



