Let us now inquire what the invertebrate fauna of the Alps teaches us. We are told by Dr. Kobelt, the great authority on European land shells, that a uniformity of character marks the Alpine Molluscan fauna (_b_, i., p. 251). One of the characteristic genera _Campylaea_--often looked upon as a sub-genus of _Helix_--is a group containing somewhat flattened conspicuous snails of large size. These are found everywhere in the Alps, and wherever they occur beyond the confines of these mountains, remarks Dr. Kobelt, their origin from the main stock is easily traced. They have been gathered in the Apennines in Sicily, and even beyond the Mediterranean in Algeria. On the Balkan peninsula they occur right down to the most southern point of Greece, but are not met with either in Crete or Asia Minor. One species has been found sub-fossil in Thuringia in Northern Germany. Another truly Alpine genus, says Dr. Kobelt, is the operculate _Pomatias_, which in its geographical distribution offers some interesting modifications from that of _Campylaea_. Less limited to high elevations, it has spread over a greater part of the plains. This has happened especially in France, while in Germany one species advances almost as far north as Heidelberg. In other directions 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 _Campylaeæ_ 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.