1132 ON NEW OR RARE VERTEBRATES FROM THE HERBERT RIVER, 



Though a decidedly larger animal than P. mongan its skull is 

 distinctly smaller, somewhat shorter, and in a greater ratio nar- 

 rower between the zygomatic arches across the palate and in the 

 teeth, which however present no other appreciable difference. The 

 frontal crests are feebler and the parietal crests rise less high and 

 more angularly upon the sides of the cranium. 



Different as the two females are side by side, it was but natural 

 to attribute P. mongan £ to P. herbertensis £, as long as the other 

 sex of each was absent. 



The Brill. 



The Brill is the Flying Phalanger of the scrubs which clothe the 

 tops of the Main Range, north of the Herbert River. In almost 

 all its superficial characters it is not to be distinguished with 

 certainty from the long and well known Petaurist, P. taguanoides, 

 of the forest plains ; but from all Queensland examples of tagua- 

 noides in the hands of the writer it is externally differentiated 

 by the shortness of its ears. This peculiarity would have failed to 

 create more than a passing suspicion of its distinctness, had not an 

 examination of the skull suggested by it, revealed differences which 

 appear to show that it has some real significance. In general form 

 and proportions indeed the skull closely resembles some Queensland 

 crania of taguanoides, but structurally it differs from them all in 

 at least one rather important particular, the size and shape of the 

 tympanic canal. This in taguanoides is constantly wide, cylindrical 

 and conspicuously exserted — in the subject under notice the free 

 outer wall of the tube is flattened and so much adpressed as to 

 be barely visible on the lateral aspect of the cranium when viewed 

 from behind. The meatus is thus rendered comparatively narrow 

 and its aperture oval. A modification in one organ naturally invites 

 attention to another, and turning, not without expectancy, to the 

 teeth, we find in them individually and serially indications of 

 changes taking place which are the more valuable in that these 

 organs are in taguanoides proper subject to very little variation. 

 The molar battery is considerably shortened — its length in the upper 

 jaw goes 3J times into that of the entire skull, whereas in the 



