In Ph. platyrhinus (PI. XLIX. fig. 6) and Ph. vombatus the two divisions of the supra- 

 tympanic cell are more equal, and the ' gomphosis ' of the squamosal with the tympanic 

 is less marked. The malar part (PI. XL VI. fig. 1, 26) of the zygoma defines the orbit 

 posteriorly by an angular process in both the bare-nosed Wombats ; it is not developed 

 in the hairy-nosed species, where the hind boundary of the orbit is indicated by the post- 

 frontal process (PI. XLIX. fig. 1, 12) which is not present or is rudimental in the others. 



The numerous irregular venous foramina of the squamosal (Pis. XLVI. & XLVIL 27) 

 are notable in all the species of Wombat. 



The superior maxillary sends outward and backward a process (PI. XLVIII. fig. 1, 21* ) 

 which contributes to and strengthens the anterior pier (ib. 26) of the zygomatic arch ; 

 it projects above the alveolus of the third and fourth molar teeth, at a greater height 

 above the molars in Ph. latifrons (p. 320, fig. 6, 21*) than in Ph. platyrhinus (ib. fig. 5) 

 or in Ph. vombatus. In a skull of the larger bare-nosed species, with an upper molar 

 series 2 inches 2 lines in extent, the process rises 7 lines above the outlet of the third 

 molar alveolus. In the skull of a Ph. latifrons with a molar series 1 inch 11 lines in 

 extent, the process rises 10 lines above that outlet. In other words, the outer alveolar 

 plate of the maxillary is deeper below the zygoma in the hairy-nosed than in the bare- 

 nosed Wombats ; it is also more nearly vertical, less inclined mesiad as it descends to 

 the outlets of the sockets. 



Phascolomys vombatus resembles Phascolarctus and Hyjysiprymnus in having the pos- 

 terior palatal openings large and situated entirely in the palatal bones ; and posterior 

 and external to these are two small perforations, not present in the Kangaroos, but 

 which in the Koala and Wombat terminate below a vertical canal opening upon the 

 back and outer part of the maxillary. In the two larger species {Phascolomys 

 platyrhinus and Ph. latifrons) the generic characters of the postpalatal apertures are 

 repeated. Of two skulls of Ph. platyrhinus, in the British Museum, the postpalatal 

 apertures are longitudinally elliptical or oblong in one (PI. XLVIII. fig. 1, b) and are 

 triangular in the other ; in both, the apertures extend more forward and come near to 

 the transverse parallel of the middle of the hindmost socket (ib. ib. «3). In three 

 skulls of Ph. latifrons the postpalatal foramina (PI. XLIX. fig. 1) are relatively larger, 

 especially longer, than in either the Tasmanian or platyrhine Wombat, and are rounded 

 anteriorly but less broad there than behind : they advance nearer to the fore part of the 

 last molar alveolus, or reach that transverse parallel. The intermolar part of the bony 

 palate is more contracted anteriorly in the bare-nosed (PI. XLVIII. figs. 1, 4, 21,21) than 

 in the hairy-nosed Wombats (ib. fig. 5, 21 ; PI. XLIX. fig. 1, 21) ; the narrowest part is 

 between the right and left second molars in Ph. platyrhinus and Ph. vombatus ; but 

 in Ph. latifrons there is little difference in the interval between the second (di) and 

 that between the first (d 3 ) molars. The palate is slightly arched transversely, and is 

 almost flat in some platyrhine Wombats. In the latifront species it is always more 

 vaulted, or deeper when viewed from below, at the diastemal part (PI. XLIX. fig. 1, 21), 

 especially at the prepalatal openings (ib. a, a) than in the bare-nosed species ; and the 



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