Nf^TK. — 111 llie maps wliich illustiatc tlic ininialions (lE 

 ilu" following species an atteniiit lias been made to trace 

 tlicir course by separating and grouping the different move- 

 ments, l)ut it must be understood that this grouping is to :i 

 certain extent artificial and is only done for the sake of 

 clearness. "J hese successive immigrations are indicated in 

 the maps by the following signs : — 



First immigration thus : — 



Second „ „ (5) 



Third „ „ Qo] 



Fourth ,. „ <^ 



Fifih .. ,, (29) 



Sixth 



<^ 



