No. 410.] THE EUROPEAN FAUNA. 105 
belonging to the Norwegian lemming type have lately been 
discovered in Portugal, since it is one of Dr. Scharff’s criteria 
of a Siberian migrant that it does not occur south of the Alps 
or Pyrenees, were it not for the impossibility of ascribing an 
American origin to this species. As I have shown that none 
of the other Arctics can have come that way, and as the lem- 
ming otherwise agrees so well with them in their present and 
past distribution, I think there can be no difficulty about refer- 
ring them to the same category. 
Nor can I endorse Dr. Scharff's treatment of the various 
ptarmigans (Lagopus) On page 336 he sums up his conclu- 
sions to the effect that ** Z. albus and L. mutus appear in our 
continent chiefly! as Arctic migrants." His reason for so 
regarding the former is given on page 334, where it is stated 
that “no doubt the British grouse is a descendant of the Scan- 
dinavian willow grouse. The latter is known also to inhabit 
Greenland and Arctic North America, and is even found beyond 
Bering Straits in northern Siberia." In the first place, as the 
British grouse (Lagopus scoticus), with its brown wing-feathers, 
is almost certainly nearer the original common ancestor of the 
willow grouse,? it would be the Scandinavian willow grouse 
(L. albus) which must be regarded as the descendant, if there 
really be a direct line of descent between the two, and not vice 
versa. In the second place, it is easy to show that the geographi- 
cal distribution of Z. a/bus is not that of an Arctic species in 
Dr. Scharff's sense. It will be noted that he gives Greenland 
among the localities where this species is found. But it is one 
of the peculiarities of the distribution of this species that it 
does not occur in any part of Greenland. It is also absent in 
Spitsbergen and Iceland, and a route of immigration from 
America by any one of these countries is consequently out of 
! On page 334 he regards the latter both as Arctic and Siberian; see also page 142. 
* The Probability that the dark wing color of Z. scoticus might be the result of 
reversion is very remote. In a species so variable in its coloring we should in 
such à case expect a very frequent cropping out of so universal a character imme- 
diately and comparatively recently preceding the last change: It must be m 
bered that the white wing-feathers are characteristic of all the other species and 
Orms of the genus, and that they are not subject to seasonal color changes like 
the rest of the plumage. 
