rections also the genus
has travelled beyond the limits of range of _Campylaea_. _Pomatias_
occurs in the Pyrenees and Northern Spain, in Sardinia and Crete, and
may, according to the same author, be expected in Asia Minor, although
no species has as yet been met with there. In Greece, again, it has been
observed, and numerous species inhabit Tunis and Algeria. Dr. Kobelt
connects the wider range of _Pomatias_ with the geological history of
the genus (_b_, i., p. 253). He tells us that species of Pomatias have
been found in eocene deposits differing but little from our present
forms, while undoubted _Campylaeae_ are not met with till we reach the
upper Miocene.

_Zonites_ is, according to Dr. Kobelt, a third Alpine genus, whose range
scarcely differs from the other two (_b_, i., p. 254). The centre of
distribution lies at present in one of the branches of the most southern
Alpine chain which help to form a large portion of the Balkan peninsula.
The bulk of the species inhabit that peninsula, the Greek Islands
(except Crete) and Asia Minor. Neither in the Tyrol nor in Switzerland
do we find any _Zonites_, and the few species that do occur in the
south-eastern Alps only just cross the outliers of these mountains.
Between the south-western Alps and the Rhone we again find a
_Zonites_--a remarkable case of discontinuous distribution, since the
nearest other habitat of the genus is Monte Gargano in South-eastern
Italy, which is known to harbour a good many interesting geographical
puzzles.

We still have a good deal to learn as regards the molluscan fauna of
Sicily, Sardinia, and Corsica. These islands have scarcely been more
than skimmed by conchologists, and _Zonites_ may inhabit one or all of
these, which might indicate to us the manner in which this genus
travelled from Southern Italy to Provence in the south of France. The
distribution of _Zonites_ certainly does not seem to imply an Alpine
origin, because it is almost completely absent from the Alps proper.
But I do not think my views differ materially from those of Dr. Kobelt,
since the Alps, in the wide sense, include the mountains of the Balkan
peninsula, where I should feel inclined to locate the ancestral home of
the genus.

The small operculate genus _Acme_ is a similar case. Dr. Kobelt places
the centre of distribution on the southern slope of the Alps, but
scarcely any of the species inhabit the Alps proper. Some occur in
France, others in North Africa, Sic