396 



EEEUNETES. 



Ancient 

 routes of 

 emigration. 



If we regard the ancestors of the genus Ereunetes as residents on the shores of the 

 Polar Basin before the Post-Phocene Glacial Epoch, and as having been driven south by the 

 Arctic cold into isolated regions, where they became differentiated into four species, there 

 cannot be much doubt that the ancestors of JE. taczanowshii followed the Pacific coast of 

 Asia. E. scolopaceus, being its nearest relation, doubtless took the Pacific coast of America, 

 and, after its return to the Polar Basin, was in post-glacial times again partially isolated and 

 partially dififerentiated east and west of the Rocky Mountains, the eastern colony becoming 

 E. griseus. E. pusillus and E. himantopus appear both to have originated east of the 

 Eocky Mountains. As the former has extended its range, probably in post-glacial times, 

 to Alaska (where it has become partially differentiated as E. occidentalis), we may perhaps 

 assume that it followed the inland chain of lakes, whilst the latter may have selected the 

 Atlantic coast of the American continent. This hypothesis is supported by the fact that 

 the larger species appears to be more exclusively a coast bird on its autumn migrations. 



"S ^ 



E. scolopaceus 

 (winter plumage). 



E. griseus 

 (summer plumage). 



EREUNETES GRISEUS. 



CANADIAN 8NIPE.EILLED SANDPIPER. 



Diagnosis. 



Ereunetes dorso postico quam dorsum superius valdfe pallidiore : palam^ nulla inter digitum 

 medium et digitum iuteriorem. 



