SPECIES OF THE GENUS NUMENIUS. 143 
Of the two species with dark rumps and uniformly striated 
crowns, one breeds in East Siberia and the other in sub-Arctic 
America. As the latter is more common on the Pacific coast of 
that continent than on the Atlantic, there is every reason to 
suppose that this group represents the Curlews which emigrated 
through Behring Straits along the American shores of the 
Pacific. 
Neither of the two species with Whimbrel markings on the 
head, dark rumps, and barred wings, are found in the Old 
World, except that one of them is said to have occurred in 
Kamtschatka. They probably came down Baffin’s Bay, as the 
Hudsonian Whimbrel has occurred in Greenland and once in 
Iceland. It is uncertain whether the Pacific Island Whimbrel 
breeds in Kamtschatka or in Alaska, but at all events it appears to 
be unacquainted with the coasts of China. 
The pale-rumped Whimbrel is so common in Iceland and the 
Faroes that it is natural to suppose that it emigrated to the 
Arctic Regions of the Old World by way of those islands along 
the east coast of Greenland, where it is still found, and whence 
it has gradually spread to East Siberia. In the latter locality 
its rump is considerably streaked, leading to the supposition 
that when its range first touched that of its dark-rumped allies 
the species had not become quite so completely differentiated as 
they appear to be now, and that consequently some interbreeding 
took place between them, which has left its permanent mark on 
the eastern form of the Common Whimbrel. 
The Pale-rumped Curlews, being represented by two species 
in Europe, one in Asia, and being entirely absent from America, 
doubtless escaped from the ice from the Kara Sea, along the 
European coast, and up some of the great rivers of Western 
Siberia. 
The first group to be considered may be described as Pale- 
rumped Curlews. They may be diagnosed as having the rump 
white, or white more or less streaked with brown, but with no 
mesial line on the crown. They represent the Atlantic coast 
Curlews of the Old World, and consist of two species, one of 
which is perhaps divisible into two subspecies. 
