The relationship between the palaearctic and nearctic faunas 



279 



R«pn>di*c*<«t tM OaodaiNt InsMui. f 



FIG. 47. Distribution of long-winged (white) and short-winged (black) Bembidion 

 grapei Gyll. (fig. 44) in Greenland. Most of the few long-winged specimens are 

 found near the periphery of the species' area, in the north and the south. 



The best criterion for the existence of the Scotland-Greenland bridge during 

 any of the interglacial periods would be the discovery of contemporaneous de- 

 posits in Scandinavia indicating an arctic climate contrasting with temperate, or 

 warmer, conditions in central and western Europe. Until then the dating of 

 this land-connection, which from a biogeographical point of view seems inevitable, 

 must probably be postponed. 



Meanwhile it is highly desirable that botanists reconsider the problems of 

 "Westarctic" and other Amphiatlantic plants, and also of the Greenland flora, 

 from a more realistic point of view. Above all these ought to be treated by careful 

 investigation, including experiments, of seeds and other diaspores, in order to 

 get a clear idea of their different modes of dispersal. Speculations founded exclu- 

 sively on maps of distribution, as now often happens, do not give satisfactory re- 

 sults. In this way, botanists would also be able to approach the real nature of a 



