60 BONE BRECCIA DEPOSIT, 



satisfactory explanation of the disappearance of the small Dipro- 

 todonts. It is at present, however, impossible to say more than 

 that at the time of the deposit Dasyures were absent or rare, 

 that in more recent times they have become numerous in the 

 district, and that their introduction or increase has been the 

 probable cause of the destruction of the smaller forms. The 

 fact of Pfitaurus breviceps having not only survived but 

 increased, while the closely allied Dromicla has been all but 

 exterminated, seems to suggest that the former with the parachute 

 expansions was able to escape from some enemy to which Dromicla 

 fell a prey. Pala',op'',lanrus, if we may assume, as is quite 

 probable, that it resembled GumaohdldeuH in being without 

 lateral expansions, would fall as easily a prey as Drom'cia. 



I must acknowledge my indebtedness to Mr. J, J. Fletcher, 

 Mr. R. Etheridge, Junr., Mr. De Vis, and to my father for kind 

 assistance they have rendered me. 



EXPLANATION OF PLATES. 

 Plate VI. 



Macropus ivombeyensis. 



Fig. \. — Right jaw — nat. size. 



Fig. 2. — Right lower teeth — nat. size. 



Fig. 3.— Lower p^ ( x 3). 



Potorous tridacfylus, var. antiquum. 



Fig. 4. — Left upper molars ( x 4'5). 



Fig. 5. — P3 (left upper ?) ( x 4-5). 



Fig. 6.— Left upper p (4'5). 



Fig. 7.— Right lower p^ ( x 5). 



Plate VII. 

 Burramys parvus. 



Fig. \. — Side view of skull of ( x 3 '4). The lower jaw is seen somewhat 

 obliquely to represent its true side view when placed in the 

 skull. 



Fig. 2. — Upper aspect of fragment of skull ( x 3*4). 



