48 THE ZOOLOGIST. 
through on spring and autumn migration; but a few remain to 
breed in the delta of the Rhone and on the Adriatic coast, where 
also a few remain during winter. It winters on both coasts of 
Africa, on the west as far south:as Senegambia, and on the east 
as far south as Mozambique. It is a resident in the Caucasus, 
but to the valleys of the Don and the Volga, and to the lakes and 
rivers of Western Siberia and Turkestan, it is a summer visitor, 
wintering on the Mekran coast and the west coasts of India as far 
south as Ceylon.” 
The West Coast of Africa south of Morocco appears to have 
been of such a desert character that the Oystercatchers were 
afraid to emigrate further in that direction. The basin of the 
Mediterranean, on the other hand, provided the necessary outlet 
for the surplus population, and the stream of emigration continued 
to flow eastwards from sea to sea, lake to lake, and river to river, 
at least as far as the Obb. The advanced party appear to have 
pushed forward still more to the east, and to have reached the 
valley of the Amoor, whence they never returned, but, following 
the course of that river to its mouth, they established an inde- 
pendent colony. The cessation of interbreeding between the 
birds of this colony and the parent stock soon caused a variation 
between them, and the eastern birds are now generally regarded 
as specifically distinct, but the difference, though constant, is 
very slight. 
8. Hematopus osculans. — The Japanese Oystercatcher only 
differs from the British species, with which we are familiar, in 
having on an average a longer bill, in having the upper tail-coverts 
more constantly tipped with black, and in having much less white 
on the wings. The white on the outside web of the primaries 
does not appear until the sixth quill, and on the inside web not 
until the second quill; whereas in the European bird the white 
on the outside web appears on the third quill, and that on the 
inside web on the first. The range of the Japanese Oystercatcher 
extends for perhaps a hundred miles up the Amoor, and north- 
wards to the shores of the sea of Okotsk, between East Siberia 
and Kamschatka. Southwards it reaches the shores of North 
China, and in winter those of South China. They still appear to 
retain some tradition of their western origin, and occasionally a 
bird will attempt to find its way back again across country, and 
appear as an unwonted visitor in Burma or Arrakan. 
