egarded as having reached
them in the normal mode, viz., by migration on land. According to Mr.
Beddard (p. 138), it is difficult to see how earthworms could be
transported across the sea. Floating tree-trunks have been observed far
out at sea, but unless the water remained absolutely calm during the
long period necessary for the drifting by currents so that no splashing
occurred, the worms would probably be killed. Yet earthworms do occur
on oceanic islands. It is indeed quite possible that our views with
regard to the origin of the remainder of the Pacific Islands may change
very materially, and once more revert to what Dr. Gould expressed nearly
fifty years ago in the following words: "From a consideration of the
land-shells on the Pacific Islands, it seems possible to draw some fair
inferences as to the relations of the lands which once occupied the area
of the Pacific Ocean, and whose mountain peaks evidently now indicate or
constitute the islands with which it is now studded." Indeed Dr. von
Ihering goes so far as to positively state that in his opinion the
Polynesian Islands are not volcanic eruptions of the sea floor, which
being without life were successively peopled from Australia and the
neighbouring islands, but the remains of a great Pacific continent,
which was in early mesozoic times connected with other continental land
masses (_a_, p. 425).

Before coming to a decision on the part played by flotsam and jetsam in
the constitution of an island fauna, those who have studied the problem
on the spot should, however, have a voice in the matter. And though,
from my experience in northern latitudes, I feel sure that island faunas
there are but slightly affected by occasional dispersal of species, Mr.
Hedley, who has made the fauna of the Pacific Islands his special study,
assures me that drift migration plays an important _role_ in that
region. I hope we may soon have a more detailed account of his
particular observation bearing on this interesting subject.

On the other hand, Mr. Simpson, who has gained considerable experience
of oceanic dispersal in the West Indian region, though he acknowledges
having often noticed bamboo rafts, which would be suitable in the
transportal of invertebrates, nevertheless does not attach much
importance to this means of distribution. "The fact," he remarks, "that
the operculates (operculate land-shells) form so large a proportion of
the Antillean land-snail fauna, that a majori