i83 3 .] 
Analyses of Books . 
39 
France he found that birds “appear to migrate low, principally 
by day, and to follow the coast-line.” He now concedes that 
birds, in crossing the sea, “follow ancient coast-lines.” There 
is no doubt that birds flying northwards in France would find the 
coasts of the Bay of Biscay an excellent guide. Nor can we 
wonder that those which cross the Channel should take the “ short 
sea route ” from Calais to Dover. Hence it is not surprising if 
certain migratory species are more common in the south-eastern 
counties of England than in the south-west. It remains to be 
traced what birds of passage, if any, cross over diredt from the 
Continent to Ireland, and which pass by way of England. The 
migration via Italy and Germany, and those through Greece to 
Hungary, and by way of the Dardanelles to Bulgaria and Ruma- 
nia, have still to be studied. The contingent for Illyria, Hungary, 
&c., certainly seems to follow the Dalmatian coast. He considers 
that the origin of migration does not probably date back to before 
the Glacial epoch. “ The more one sees of migration the less 
it looks like an instinct which never errs, and the more it seems 
to be guided by a more or less developed reasoning faculty which 
is generally right, but occasionally wrong.” The whole of this 
chapter will well repay a most careful study both on the part of 
the observer and of the philosophical zoologist. 
The ornithological results of Mr. Seebohm’s expedition, though 
somewhat lessened by various mishaps, especially by two ship- 
wrecks, which, as he drily observes, “ did not form a part of my 
original programme,” were still numerous and important. He 
complains of the manner in which Pallas, the pioneer of Siberian 
ornithology, has been treated by systematists. That able ex- 
plorer found many species of Siberian birds closely allied to 
West European species, but still distinguishable. To such forms 
he gave names, and to those names modern writers have shown 
scant justice. “ In some cases, where they have had an oppor- 
tunity of comparing examples from Siberia with West European 
skins, they have admitted the validity of his species ; but in other 
cases, where they have also had access to East European skins, 
the existence of intermediate forms has been alleged as a reason 
for denying the validity of the species, and the Siberian forms 
have been passed by with a contemptuous sneer, as beneath the 
dignity of Science. In the majority of cases, however, the 
writers have never seen a Siberian skin, and Pallas’s name is 
consigned to the limbo of synonyms without note or comment. 
With these writers a form is either a species or it is nothing. 
They attempt to draw a hard and fast line where Nature has 
drawn none. They profess to believe in the theory of the deve- 
lopment of species, but they never dream of looking at birds 
from an evolutionary point of view. In their hearts they still 
cling to the old-fashioned notion of special creation.” This is 
very just criticism. The author backs up his opinions by giving 
instances of a series of forms, one extreme term of which may occur 
