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nition of the diastemal part of the bony palate, and the greater depth of the maxillary 

 below the anterior pier of the zygomatic arch in Phascolomys Mitchelli. 



§ 9. Palatine foramina in Phascolomys. — I next proceed to notice Phascolomydian 

 fossils from the freshwater deposits of Queensland, in the interpretation of which some 

 observations must be premised on the palatal foramina in existing species of Wombat. 



In my first paper on the Osteology of the Marsiqnalial state that Phascolomys resem- 

 bles Phascolarctos and Hypsiprymnus in having " the posterior palatal openings large 

 and situated entirely in the palatal bones ; and that posterior and external to these are 

 two small perforations"*. In the other two species (Phascolomys latifrons and Phasco- 

 lomys platyrhi 'nus) determined by cranial characters since the date of that remark (1838), 

 the generic characters of the postpalatal openings are repeated. These additional mate- 

 rials serve to test the statement that in Marsupials " the perforations of the bony palate 

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

 mination of recent and fossil species" f. 



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 which 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 of Phascolomys platyrhinus 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 Phascolomys latifrons the postpalatine foramina are relatively larger, 

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

 rounded anteriorly, but less broad there than behind. 



Dr. Murie§ notes the larger size of the postpalatine foramina in Phase, latifrons as 

 compared with Phase, platyrhinus, 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 



* " On the Osteology of the Marsupialia," Trans. Zool. Soc. vol. ii. p. 389. 



t Ibid. p. 388. 



X Ibid, plate lxxi. fig. 6. 



§ Loc. cit. p. 844. 



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