806 DR. J. MUKIE ON PHASCOLOMYS PLATYRHINUS. [JuilC 2", 



In P. lutifrons, from the altered distribution of the dorsal and 

 lumbar vertebrae, the metapopliyses, commencing sometimes at the 

 eleventh and sometimes at the twelfth dorsal vertebra, continue to 

 increase in size to the fourth lumbar, after which they diminish as 

 in the other species. 



The anapophyses, which in P. platyrhinus and P. wombat are 

 first observable on the eleventh dorsal, in P. latifrons make their 

 appearance very rudimentally on the eighth and ninth dorsal. The 

 diminution of these processes in the lumbar and disappearance in 

 the last of the series are alike in the three soecies. 



Bones of the pelvis of I\ phifyrhinus. One-third nat. size. 



Lumbar VertebrcB. — From these being only four in number, as 

 well as from their having a wider stretch of transverse processes, P. 

 platyrhinus and P. loombat possess short, broad loins ; whereas in 

 P. latifrons the lumbar region is narrow, elongated, and conical in 

 shape. The average proportional length of the lumbar region be- 

 tween the three species is respectively 4^, A^ and 6^ inches, — the 

 dorsal region contrariwise measuring 12 



|, 10 and 9^ inches in the 



