BY K. M. JOHNSTON, F.L.S. 



13 



cause or root of the dimensions of the other two categories, 

 but it may be safelj taken as a unit measure or index of 

 them. This is significallj illustrated by the following con- 

 trasts with respect to the principal divisions of Tasmania, 

 taking a common division (40) for determining the respective 

 quotas : — 



•uop-epdoj 

 •xo.xdd Y 



