The History of the European Fauna Part 14

We are told by Sir Archibald Geikie (p. 851) that "from the Pyrenees eastwards, through the Alps and Apennines into Greece, and the southern side of the Mediterranean basin, through the Carpathian Mountains and the Balkan into Asia Minor, and thence through Persia and the heart of Asia to the sh.o.r.es of China and j.a.pan, a series of ma.s.sive limestones has been traced, which, from the abundance of their characteristic foraminifera, have been called the Nummulitic Limestone. Unlike the thin, soft, modern-looking, undisturbed beds of the Anglo-Parisian area, these limestones attain a depth of sometimes several thousand feet of hard, compact, sometimes crystalline rock, pa.s.sing even into marble, and they have been folded and fractured on such a colossal scale that their strata have been heaved up into lofty mountain crests sometimes 10,000, and in the Himalaya range more than 16,000 feet above the sea." "Nowhere in Europe," continues the same author (p. 860), "do oligocene strata play so important a part in the scenery of the land, or present on the whole so interesting and full a picture of the state of Europe when they were deposited, as in Switzerland. Rising into ma.s.sive mountains, as in the well-known Rigi and Rossberg, they attain a thickness of more than 6000 feet." "By far the larger portion of these strata is of lacustrine origin. They must have been formed in a large lake, the area of which probably underwent gradual subsidence during the period of deposition, until in Miocene times the sea once more overflowed the area."

From these remarks by our most eminent British geologist, we gather that in early Tertiary times much of the present area of Switzerland was either a sea or a large freshwater lake. The Alps were then appearing in this sea, probably as a chain of islands, and in the beginning of the Miocene Epoch one large elongated island had made its appearance--the future European Alps. I have already mentioned that the Miocene Sea skirted the Alps from the Mediterranean up the valley of the Rhone and along its northern and eastern margin. Miocene marine deposits are also known from the Southern Alps and the east side of the Apennines, from Corsica, Sardinia, and Malta. No trace, however, of them has been noticed anywhere along the aegean Sea or on the Balkan peninsula. The Alps were therefore connected to the east with the outliers of the Balkan Mountains, and in this way with Asia, from which they received so large a proportion of their fauna and flora. In pliocene times the sea still washed the southern sh.o.r.e of the Alps, but to the north dry land gradually supplemented the sea, and the Alpine fauna and flora were able to pour into the plain. It was then that the Arctic species--which we have learned had migrated into Northern Europe from the north--found their way to the Alps. In a similar way Lusitanian forms--in fact, species from almost all parts of Europe--were now free to wander to the newly opened up peninsula which had become part of the mainland of Europe. The typical Siberian species had not entered our continent at that time, it was not till much later--not until the middle of the Pleistocene Epoch--that they made their appearance at the foot of the Alps, but, as we shall see later on, it is doubtful whether many of these species ever reached the mountains.

The fauna of the Alps, and also the flora, is therefore made up of a number of component elements. In the first place we have the Oriental element--the migrants from Central and Southern Asia. When the nature and origin of the Oriental fauna in Europe was discussed, reference was made to the fact (p. 272) that we can distinguish an older from a newer Oriental migration. Both of these have entered the Alps. As we might antic.i.p.ate, many of the older Oriental migrants have developed into new species, laying the foundation of an indigenous Alpine element. From the fact that they set foot on the Alpine peninsula, it might be expected that there could have existed no mountains to speak of. The climate was mild and damp. Now as the country rose, and a formidable mountain range took the place of a hilly island, the whole fauna was lifted up and transferred to entirely different conditions. A modification of their structure to suit the new surroundings was therefore to be antic.i.p.ated, and that is exactly what occurred, though not in all cases.

Take, for example, the goats which are of Asiatic origin. Every one has heard of the "Steinbock,"--the Alpine mountain goat (_Capra ibex_)--though very few have seen it in its native haunts, where it is now on the verge of extinction. A closely allied species (_Capra sibirica_) inhabits the Alta and Himalayan Mountains; a third species (_Capra sinaitica_) lives in Palestine, and has entered Egypt by way of the Sinaitic peninsula. Another (_C. aegagrus_) occurs in Asia Minor, Persia, the island of Crete, and some of the Cyclades. This exemplifies what I remarked in the last chapter about the former land-connection between Greece and the Asiatic continent. Finally, we have the Pyrenean Goat (_Capra pyrenaica_), which is found in the Pyrenees, the higher ranges of Central Spain, in Andalusia, and Portugal, thus indicating that it probably reached the Spanish peninsula from the south by means of the old Sicilo-Algerian highway, especially as remains of the species occur in the cave deposits of Gibraltar. The ancestors of the goat-like Antelope--known as the Chamois (_Rupicapra tragus_)--no doubt also came from Asia. The genus is not represented there, but _Nemorhdus_ and _Budorcas_ are allied Asiatic genera, while the Rocky Mountain Goat (_Haploceros monta.n.u.s_) also has certain affinities with the Chamois.

Besides the Alps, the latter occurs in the Caucasus and the Pyrenees.

The Alpine Marmot (_Arctomys marmotta_) is sometimes quoted as owing its origin to the Siberian pleistocene migration, but it does not occur in Siberia now, nor is there any palaeontological evidence that it was ever found there. The genus _Arctomys_ is an ancient Asiatic genus, to judge from its general range. Only two species occur in Europe, one of which, the true Siberian Marmot (_A. bobac_), just enters our continent in the east--or rather, it is one of those species which came to us in pleistocene times and are now gradually retreating towards their native land. The genus, however, is probably not of Siberian origin. No less than seven other species occur in Asia, six of which are confined to Central Asia and the Himalayan Mountains, while four have wandered to North America. The sequence of events, therefore, was that the ancestor of _Arctomys marmotta_ probably came to the Alps direct from Central Asia by way of Asia Minor in miocene or pliocene times. It has since become modified into a distinct species, and has spread to the European plain, where it occurs fossil in pleistocene strata, and to the Carpathian Mountains and the Pyrenees.

The great majority of species of the large genus _Microtus_ (_Arvicola_) are Asiatic, and there can be little doubt that it has originated in that continent. There is one species of Vole (_Microtus nivalis_) which occurs in the high Alps, and which has been supposed to be a typical Alpine form. It is known, however, to occur also in North Italy and in Bohemia, while _Microtus leucurus_ of the Pyrenees is identical with this species. But its range is by no means confined to Europe, for it has also been discovered in Syria and Palestine, while a closely allied form exists in the Himalayan Mountains. This shows clearly that the species has migrated to the Alps from Asia Minor. That this migration may have taken place at an early period--at a time when Sardinia and Corsica were still connected with Southern Europe--is indicated by the occurrence of an extinct Vole (_Microtus brecciensis_) in Sardinian and Corsican pleistocene (?) deposits.

All the Alpine species mentioned except the Chamois can be easily traced to their former Asiatic home. But even it has its nearest relations in Asia. I might also refer to another Vole (_Evotomys Nageri_) which is practically confined to the Alps and Northern Italy, and which has probably originated there, though most of its nearest relations are either Asiatic or North American species.

But besides these Asiatic immigrants and their modified descendants we have a small truly native Alpine mammalian fauna. _Sorex alpinus_--the Alpine Shrew--occurs only in the Alps, the Harz Mountains, Pyrenees, and Carpathians. The genus has been found in European eocene strata,--in vastly older deposits in our own continent than elsewhere,--so that it is extremely probable that it has originated there. It may then have developed a new centre of distribution in the newly-formed Alps where both _Sorex alpinus_ and _S. minutus_ (_pygmaeus_) have their home. From there they again spread--perhaps already in miocene times--to Asia and North America, where a large number of new species originated. It seems to me even probable that one of these Asiatic species of _Sorex_, viz.

_S. araneus_ (_vulgaris_), subsequently migrated towards the old home of its forefathers, since we find it more or less confined to Central and Northern Asia and Northern Europe.

Though the origin of the Alpine Hare has already been referred to and fully discussed in a previous chapter (p. 148), the conclusions arrived at may be once more repeated. The Alpine Hare (_Lepus variabilis_) is of Arctic origin. It spread southward into Europe, North America, and Asia in early glacial times, and reached our continent from Spitsbergen by means of a direct land-connection with Lapland. The Scandinavian peninsula was then separated from Russia, but connected with Scotland and Ireland (Fig. 13, p. 170). Since England was then united to France, the Alpine Hare was able to invade western continental Europe and all the mountain ranges. Its range is very discontinuous, small colonies being scattered all over the mountainous parts of the Northern Hemisphere, while the European Hare--a closely allied species--occurs in the plain, and now occupies to some extent the former haunts of the Alpine Hare (cf. Fig. 8, p. 137). Might not the European Hare, as suggested, possess some advantages which enabled it to drive the other into more inaccessible parts, thus producing the peculiarity of range?

The present distribution of the Alpine and the European Hare (_L.

Europaeus_) appears to me to strongly support such an a.s.sumption. It is not the cold which has driven the Alpine Hare to the Alps; and its presence there is not, as is often supposed, a "_standing testimony of a former arctic climate_" in Europe, but merely the necessary consequence of the weaker species being thrust into less accessible regions by a stronger rival.

_Muscardinus avellanarius_,--the common Dormouse,--though by no means confined to the Alps, has probably originated there. It is found up to a height of nearly 5000 feet in these mountains, and is spread over Europe at nearly equal distances from the Alps in all directions. Being absent from Ireland, Scotland, Norway, and Northern Russia, it seems as if it had only diffused northward in more recent times.

The closely allied genus _Myoxus_ is likewise of European extraction, some species being known from French eocene deposits.

There are only a few typically Alpine Birds. One of these is the Alpine Accentor (_Accentor collaris_), which on rare occasions visits England, and Northern Europe generally. It is, however, by no means peculiar to the European Alps; a variety of this species occurs in Central Asia, Eastern Siberia, and j.a.pan. The only other Accentor inhabiting our continent is the Hedge Accentor (_A. modularis_), which is resident over the greater part of it, and also in North Africa and the Mediterranean Islands. It also extends its range across the aegean Sea to Asia Minor, so that really not a single Accentor is peculiar to Europe.

Both the European species are evidently old forms, and the genus, as might be expected, is certainly Asiatic. No less than ten other species of Accentor are known, all of which are confined to Central Asia and the Himalayan Mountains, and are therefore all Holarctic. I may mention that much difference of opinion still exists as to the true zoological position of this anomalous genus. It has been located in several different families by various ornithologists, but has not yet found a permanent resting-place. Another bird generally considered to be peculiar to Switzerland is the Alpine Chough (_Pyrrhocorax alpinus_), but its range extends across Asia Minor to the Himalayas. Whether the European Chough should not form a distinct genus is a matter of opinion.

Some of our leading ornithologists, like Dr. B. Sharpe, are inclined to separate it from _Pyrrhocorax_; however, there is no doubt that it is closely related to the Alpine Chough, whatever view we may take of the generic distinctness. It inhabits princ.i.p.ally Western and Southern Europe, also North Africa; and its range extends eastward to the Himalayas, China, and Eastern Siberia. If any doubt still existed as to the Asiatic origin of the Choughs, it may be noted that the only two other closely allied genera, viz., _Corcorax_ and _Podoces_, live in Australia and Central Asia respectively.

There are two other birds to which I should like to refer. These are the Rock Sparrow and the Alpine Snow Finch. The first of these (_Petronia stulta_) is by no means peculiar to the Alps. It is the only species of the genus inhabiting Europe; and besides the Alps it occurs in Southern Europe generally, and ranges as far west as the Canaries and Madeira.

Eastward it is not found beyond Central Asia. Of the remaining five species of _Petronia_, two occur in Asia (including India) and three in Africa. Whether the genus is African or Asiatic is immaterial for our purpose, since, in any case, the only European species came to us from the east with the Oriental migration. The distribution of the Alpine Snow Finch (_Montifringilla nivalis_) is very similar to that of the birds we have just been considering. It inhabits the Alps up to a great height, but occurs also on the Pyrenees and other South European mountain ranges as far east as Palestine, where again it is found in the Lebanon. The genus _Montifringilla_ has seventeen other species. Twelve of these live in Central Asia and j.a.pan, extending as far north as Kamtchatka, while five inhabit Western North America right down to Mexico. There is every probability that in this case also we have to deal with an Asiatic genus which spread eastward to America, and westward to Europe.

As regards the Reptiles, there are _no_ peculiar Alpine forms, but among the Amphibia some species deserve to be mentioned. Up to an elevation of 10,000 feet we find in the Alps the Black Salamander (_Salamandra atra_); and it is apparently quite peculiar to them, never having been observed in the plains. The handsome black and yellow Salamander (_Salamandra maculosa_)--so well known as a terrarium specimen--likewise occurs in the Alps, and it has besides a fairly wide distribution in Europe. It is known from Southern Germany, the Pyrenees, Spain, Portugal, Sardinia, Corsica, Greece, Syria, and Algiers. A third species (_S. caucasica_) inhabits the Caucasus. The evidence of distribution here points emphatically to an Alpine origin of the genus _Salamandra_.

We cannot tell where the ancestors of _Salamandra_ may have come from, but several other genera of _Salamandridae_ are certainly Asiatic. Our common Newt (_Molge vulgaris_) belongs to a genus with nineteen species, several of which are peculiar to Europe. The general range of the genus, however, extends to North America, and it is more probable therefore that it originated in Asia. If so, it certainly must have pa.s.sed into Europe at a very early date. Let us a.s.sume the first _Molges_ to have traversed the aegean Sea on _terra firma_ to Greece in miocene times, they might thus have been able to travel straight on to the old Tyrrhenian continent of which Corsica and Sardinia now form the remains, and also on to North-west Africa. Indeed, we find high up in the Corsican mountains an interesting large brownish-grey Newt (_Molge montana_), and another in Sardinia (_Molge Rusconii_). Again, in Algiers there are two species, viz., _Molge Poireti_ and _M. Hagenmulleri_, while the Moroccan _M. Waltlii_ pa.s.ses into the south of Spain. Here _Molge boscae_, _M. aspera_, and _M. marmorata_ originated, the latter pa.s.sing into France.

Another branch of the _Molge_ tribe turned northward from Greece towards the newly forming Alps; and there originated _Molge alpestris_ and _M.

palmata_, which more recently have spread into England (one at least), Germany, France, Austria, and Southern Italy. _Molge vulgaris_ is an Asiatic species which wandered northward after entering Europe, covering a large area, but never reached the extreme south or south-west. _M.

cristata_--the large Water Newt--has a similar but not quite so extended a range, while _M. vittata_ never managed to cross the borders of Asia Minor. Some of the other species occur in China, j.a.pan, and North America.

None of the tailless Batrachians--the Frogs and Toads--are peculiar to the Alps, but one, viz. _Rana temporaria_, ascends to the height of no less than 10,000 feet. It is our common British Frog. No other Frog probably ranges so far north or to such heights.

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 sh.e.l.ls, 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 _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, Sicily, Southern Italy, and the Caucasus. It is evidently a very ancient genus. The species live in moss or underground, and are not likely to be transported across the sea by accidental or occasional means of distribution.

Still another genus, which resembles _Acme_ in its geographical distribution, is _Daudebardia_--a small slug-like mollusc with a tiny sh.e.l.l. It does not, however, range nearly so far north or west as _Acme_, for it occurs neither in the British Islands nor in Spain or the Pyrenees.

I shall not be able to refer to more than a few of the most typical Alpine species of Lepidoptera, but they may be taken as fair examples of the geographical distribution of the rest of the group.

Even those visitors to Switzerland who do not claim to be naturalists have heard of the remarkably handsome and stately b.u.t.terfly known as Apollo. To the ardent entomologist, the first sight of this typical Alpine species is a never-to-be-forgotten delight, and he generally brings home with him a rich harvest of specimens. The more experienced b.u.t.terfly hunter knows that there are no less than three different kinds of Apollo--or, as we should say more correctly, of Parna.s.sius--in Switzerland. There is first the common Apollo (_Parna.s.sius Apollo_), then the rarer and more local _P. delius_, which inhabits more elevated regions, and finally the still scarcer _P. mnemosyne_, which is only known from the highest mountain ranges. It may be a surprise to those who have accustomed themselves to connect Apollo with the Alps, and who think the two belong together and cannot do without one another, to hear that it is by no means confined to them. It is also found in Scandinavia, France, Spain, Russia, and in Siberia. _Parna.s.sius delius_ is confined to the European Alps and the mountains of Central Asia, while _P. mnemosyne_ is known from the Pyrenees, Sweden, Hungary, Sicily, Russia, and Western Asia. One other Parna.s.sius inhabits Europe, viz., _P. Nordmanni_ of the Caucasus, but all the remaining species of the genus--and there are nearly thirty more--are confined to Central Asia. A few, as we have seen, have reached Europe, some have travelled to the Himalayan Mountains, and others to Western North America. The centre of distribution is certainly in Central Asia, and we have no reason to suppose that the original home in this case does not agree with that centre.

_Melitaea_, a genus to which some of our British Fritillaries belong, has also some typically Alpine members. Two of these, viz. _M. cynthia_ and _M. asteria_, are peculiar to the Alps, the latter being only found at considerable elevations. Most of the remaining fourteen European species are also found in Central Asia. Thus the isolated _M. maturna_, which in Europe is confined to Lapland, is also known from the Alta Mountains, which again are near the centre of distribution, since some species of _Melitaea_ range across the Northern Pacific to Western North America.

The small British Mountain Ringlet, and also the Scotch Argus, belong to a genus of b.u.t.terflies which is very characteristic of the European Alps. But owing to its enormous geographical distribution, its probable home is somewhat difficult to ascertain. Nevertheless it is a noteworthy genus, especially so from the fact that the two British species _Erebia epiphron_ and _E. aethiops_ are taken at first sight for true Arctic migrants. As neither of them, however, occurs in Scandinavia, Greenland, or Arctic America, this supposition must be abandoned. They must be looked upon as species which once had a wider range in the southern parts of the British Islands, and which have survived in a few isolated localities, where they are apparently on the verge of extinction.

About sixty species of _Erebia_ are known to science, half of which are found in Europe, the remainder in Siberia, the Himalayas, Arctic America, Chili, Patagonia, South Africa, and Madagascar. Though a few do range into these outlying regions of the earth, Central Asia seems to lie near the centre of distribution of the genus, and the probability is that it also was its original home. Most of the European species are high Alpine forms--_E. glacialis_ being met with at a height of 10,000 feet--and these are generally quite peculiar to the Alps, showing that their ancestors came from Asia at an early date, probably by way of Asia Minor and Greece. A few, as for instance _E. lappona_, range right across to the Alta Mountains from the Alps, and at least one--_E.

melas_--is found in Greece. _Erebia_ migrations seem therefore to have taken place by the Southern or Oriental route at different geological periods. But some of the European species which are more or less confined to the plain, and are either absent from Switzerland or do not reach the higher elevations, appear to me to have come by the more direct northern or Siberian highway, at a still more recent period.

These are _Erebia aethiops_, _medusa_, _ligea_, and _ambla_.

Only one species of the well-known Polar genus _neis_, viz. _.

aello_ occurs in the Alps. It has always been taken at very high elevations near the verge of the snow-line on the most lofty parts of the Simplon Pa.s.s, and other similar situations. Altogether about a dozen species of this genus of b.u.t.terfly are known, most of which are confined to the polar regions of the Old World and the New, though some have found their way to the extreme south end of South America, in what manner is still a mystery. Like the preceding genera, this also appears to have emerged from Central Asia. The genus, too, is closely allied to the last, and though its range is not quite so extensive, it resembles it in many respects. The Alpine species of _neis_ came to Europe by the Oriental route. But the Lapland species--at any rate _. jutta_ and _. bore_--have taken a somewhat circuitous route to reach our continent. They first migrated from Asia to North America, and then by the old land-connections by way of Greenland to Lapland. It is noteworthy that Professor Engler felt convinced (cf. p. 171) that the occurrence of many of the Arctic plants in North Scandinavia and Siberia could be best explained by the a.s.sumption of such a migration from Asia _via_ North America to Europe rather than by the shorter route.

There are far more Alpine beetles than b.u.t.terflies, but their geographical distribution is less well known, and it is therefore not at all safe to base important conclusions as to the origin of a fauna on that group alone; however, as far as my limited knowledge of the _Coleoptera_ of the Alps goes, their general range seems to agree perfectly with other orders of insects. Many can also be traced to an Asiatic home, and the route they came by is the Oriental and not what I have called the Siberian.

Take, for instance, the genus _Nebria_, of which we have one species in England--a black insect with a bright reddish-yellow border and long light legs--known as _N. livida_. There are about eighty European species, most of which are confined to the Alps, the Caucasus, the Pyrenees, Spain, and Greece. The genus, however, ranges all over the Holarctic Region, that is to say roughly, over Europe, Central and Northern Asia, and North America. The centre of distribution lies in Central Asia. If the genus had poured into Europe by the northern or Siberian route, we should probably now find many species in Northern Russia, Germany, and France; but this is not the case, and we may therefore a.s.sume with some justification that the Southern or Oriental route was the only one available at the time when the bulk of the species of _Nebria_ wandered to Europe. Many of the _Nebrias_ occur in Switzerland and in the Alps, generally on the margins of the snow-fields and glaciers, like _N. Germari_ and _Brunii_. Others, for example, _N.

atrata_, ascend to the highest limit of animal life, having been observed at a height of over 10,000 feet.

Of the remaining orders of insects we know as yet very little. Central Asia and even Siberia are only beginning to be explored, and their invertebrate fauna--except _Lepidoptera_ and _Coleoptera_--is practically unknown. However, I cannot conclude this short summary of some of the more characteristic Alpine animals without referring to the Gra.s.shoppers which are so conspicuous in the mountains. The mountain air simply rings during a bright summer's day with the loud and cheerful song of millions of these insects. It is one of the most vivid impressions a tourist brings back from Switzerland--this constant shrill sound issuing from an apparently invisible source.

Among these Gra.s.shoppers there are some highly characteristic Alpine genera. _Pezotettix_--formerly known as _Podisma_--is one of these. _P.

alpinus_ is almost confined to the high Alps; with _P. mendax_ it occurs in lower levels chiefly towards the south-east, that is to say, in the direction of Hungary, Servia, and Dalmatia. _P. frigidus_ occurs not only in the high Alps, but also in Lapland. _P. Schmidti_ and _P.

salamandra_ are found in Carinthia, Servia, and Transylvania; and one species also inhabits the Pyrenees and another the Italian Mountains.

Finally, the only English species of _Pezotettix_, viz. _P. pedestris_, has been taken in Sweden, Denmark, and then again in Austria, Hungary, Servia, etc., as far east as the Volga, and also on the high Alps, in Sardinia and the Abruzzi Mountains in Italy.

Very little, as I remarked, is known of the Asiatic range of this genus, but either the same or a closely allied one has many representatives in North and South America. Whether _Pezotettix_ is therefore of Asiatic origin we cannot positively affirm, but whatever view we take, the general range of the European species indicates that the migration took place from the Alps in a south-easterly direction, or to them in a north-westerly one. That is to say the Oriental route, and not the Siberian, was utilised by the migrants.

Fortunately, we know a little more about another Gra.s.shopper genus, called _Chrysochraon_. There are only two species, one of which, _Chr.

dispar_, has been found from Northern France to the mountains of Servia, but not in the Alps. The other, _Chr. brachypterus_, has a somewhat similar range in the plain; but, moreover, it inhabits the Alps up to a considerable height. It is interesting to note that both these Gra.s.shoppers again turn up on the Amur in Eastern Siberia.

In conclusion, I might mention one more Gra.s.shopper, viz. _Tettix_, because it includes a species--_T. bipunctatus_--which, though well known in the plain of Middle and North Europe, ascends the Alps to a height of nearly 10,000 feet. It is one of the few instances I know of an animal occurring in the same form in such an enormous range of alt.i.tude--from sea-level to the highest regions where animal life is known to exist. It is also known from Asia Minor and Siberia. _T.

subulatus_ has a similar distribution, but is more common in Southern Europe than the other. _T. fuliginosus_ occurs in Lapland and Siberia, _T. meridionalis_ and _T. depressus_ all along the sh.o.r.es of the Mediterranean. There can be no doubt that here also we can trace migration to or from Siberia, and again, as on previous occasions, by the Oriental route.

We now possess a fair general idea of the fauna of the Alps. We have learned that a good many of the animals are indigenous, and that others have migrated to the Alps by various routes. The majority of these have come from Central and Southern Asia with what has been described as the Oriental migration. A much smaller number have reached the Alps from the north and the west, but none of the latter are among the high Alpine forms. What will be the most surprising revelation is that the eastern species, which arrived in Europe with the Siberian migration, are practically absent from the Alps proper. No doubt some of them still survive in the lowlands of Switzerland and the Tyrol, but none of the true Alpine fauna owes its origin to the Siberian migration. If we compare the Alpine mammals with the Siberian forms which reached England (_vide_ p. 202), we at once perceive the difference. We should expect to find in the Alps--if not the Reindeer and the Glutton--the Arctic Fox, the little Pica, the Lemmings, and the pouched Marmots. It might be urged that some of the smaller Siberian carnivores and rodents do inhabit the Alps. So they do. The Stoat and Weasel have found such a congenial home in Europe, both in the plain and mountains, that they have spread rapidly to the latter, and no doubt reached within a comparatively short time the great heights at which they now occur in the Alps. But the Voles (_Arvicola_) have scarcely spread beyond the region of fields and cultivated ground. A height of 5000 feet at the most marks their maximum alt.i.tude in the Alps.

The fauna which reached the Alps in miocene and pliocene times, as well as the indigenous element, must have survived the Glacial period in their mountain home. Though I think that the conditions of the climate at that time and the size of the Scandinavian glaciers have been greatly exaggerated, there can be no doubt at all about the enormous size of many of the Alpine glaciers at this period. The climate was probably much moister but not colder than what it is now, possibly warmer. The snowfall was therefore greater, so that glaciers filled many of the lower valleys of Switzerland which are now quite free from ice, and even invaded the plain. But there is no reason whatsoever why the Alps should not even then have supported a luxuriant fauna and flora as they do now.

Possibly many of the miocene plants and animals became extinct then, but extinction of species occurs at the present day. We hear complaints that the Chamois and the Steinbock have nearly vanished; we know that the Marmot is now much scarcer than it used to be, and that the Edelweiss and many other plants are more and more difficult to find, and seem rapidly to disappear. No doubt all this is in a great measure due to the influence of man, but not altogether. There is a constant struggle for existence going on among the animals and plants themselves--the stronger and fitter species driving the less fit and weaker into a corner, where they finally succ.u.mb. This happens now just as it did in pliocene and pleistocene times, and need not imply change of climate.