XXI THE AGE OF COMPOSITE ' 249 



the order. Some means of reciprocal interchange of races between 

 these regions then existed. Then followed a suspension of the 

 means of dispersal between the tropical regions of the Old and 

 New Worlds except between the alpine heights of those latitudes. 

 (12) It is inferred by the author of this volume that the general 

 dispersion of the early Compositae over the Pacific took place 

 during the Tertiary submergence of the island-groups of the 

 Fijian region (Fiji, Tonga, and Samoa), ano that their absence 

 from that region may be thus explained. At the time of this 

 general dispersion, as above pointed out, the tribes of the 

 Compositae had been already differentiated. 



