Chapter XXII: Part III: Zoological Geography (2)

This is by far the richest portion of the Palæarctic region, for although of moderate extent much of it enjoys a climate in which the rigours of winter are almost unknown. It includes all the countries south of the Pyrenees, Alps, Balkans, and Caucasus mountains; all the southern shores of the Mediterranean to the Atlas range, and even beyond it to include the extra-tropical portion of the Sahara; and in the Nile valley as far as the second cataract. Further east it includes the northern half of Arabia and the whole of Persia, as well as Beluchistan, and perhaps Affghanistan up to the banks of the Indus. This extensive district is almost wholly a region of mountains and elevated plateaus. On the west, Spain is mainly a table-land of more than 2000 feet elevation, deeply penetrated by extensive valleys and rising into lofty mountain chains. Italy, Corsica, Sardinia, and Sicily, are all very {200}mountainous, and much of their surface considerably elevated. Further east we have all European Turkey and Greece, a mountain region with a comparatively small extent of level plain. In Asia the whole country, from Smyrna through Armenia and Persia to the further borders of Affghanistan, is a vast mountainous plateau, almost all above 2000, and extensive districts above 5000 feet in elevation. The only large tract of low-land is the valley of the Euphrates. There is also some low-land south of the Caucasus, and in Syria the valley of the Jordan. In North Africa the valley of the Nile and the coast plains of Tripoli and Algiers are almost the only exceptions to the more or less mountainous and plateau-like character of the country. Much of this extensive area is now bare and arid, and often even of a desert character; a fact no doubt due, in great part, to the destruction of aboriginal forests. This loss is rendered permanent by the absence of irrigation, and, it is also thought, by the abundance of camels and goats, animals which are exceedingly injurious to woody vegetation, and are able to keep down the natural growth of forests. Mr. Marsh (whose valuable work _Man and Nature_ gives much information on this subject) believes that even large portions of the African and Asiatic deserts would become covered with woods, and the climate thereby greatly improved, were they protected from these destructive domestic animals, which are probably not indigenous to the country. Spain, in proportion to its extent, is very barren; Italy and European Turkey are more woody and luxuriant; but it is perhaps in Asia Minor, on the range of the Taurus, along the shores of the Black Sea, and to the south of the Caucasus range, that this sub-region attains its maximum of luxuriance in vegetation and in animal life. From the Caspian eastward extends a region of arid plains and barren deserts, diversified by a few more fertile valleys, in which the characteristic flora and fauna of this portion of the Palæarctic region abounds. Further east we come to the forests of the Hindoo Koosh, which probably form the limit of the sub-region. Beyond these we enter on the Siberian sub-region to the north, and on the outlying portion of the Oriental region on the south.

{201}In addition to the territories now indicated as forming part of the Mediterranean sub-region, we must add the group of Canary Islands off the west coast of Africa which seem to be an extension of the Atlas mountains, and the oceanic groups of Madeira and the Azores; the latter about 1,000 miles from the continent of Europe, yet still unmistakably allied to it both in their vegetable and animal productions. The peculiarities of the faunas of these islands will be subsequently referred to.

It seems at first sight very extraordinary, that so large and wide a sea as the Mediterranean should not separate distinct faunas, and this is the more remarkable when we find how very deep the Mediterranean is, and therefore how ancient we may well suppose it to be. Its eastern portion reaches a depth of 2,100 fathoms or 12,600 feet, while its western basin is about 1,600 fathoms or 9,600 feet in greatest depth, and a considerable area of both basins is more than 1,000 fathoms deep. But a further examination shows, that a comparatively shallow sea or submerged bank incloses Malta and Sicily, and that on the opposite coast a similar bank stretches out from the coast of Tripoli leaving a narrow channel the greatest depth of which is 240 fathoms. Here therefore is a broad plateau, which an elevation of about 1,500 feet would convert into a wide extent of land connecting Italy with Africa; while the same elevation would also connect Morocco with Spain, leaving two extensive lakes to represent what is now the Mediterranean Sea, and affording free communication for land animals between Europe and North Africa. That such a state of things existed at a comparatively recent period, is almost certain; not only because a considerable number of identical _species_ of mammalia inhabit the opposite shores of the Mediterranean, but also because numerous remains of three species of elephants have been found in caves in Malta,--now a small rocky island in which it would be impossible for such animals to live even if they could reach it. Remains of hippopotami are also found at Gibraltar, and many other animals of African types in Greece; all indicating means of communication between South Europe and North Africa which no longer exist. (See Chapter VI. pp. 113-115.)

{202}_Mammalia._--There are a few groups of Palæarctic Mammalia that are peculiar to this sub-region. Such are, _Dama_, the fallow deer, which is now found only in South Europe and North Africa; _Psammomys_, a peculiar genus of Muridæ, found only in Egypt and Palestine; while _Ctenodactylus_, a rat-like animal classed in the South American family Octodontidæ, inhabits Tripoli. Among characteristic genera not found in other sub-regions, are, _Dysopes_, a bat of the family Noctilionidæ; _Macroscelides_, the elephant shrew, in North Africa; _Genetta_, the civet, in South Europe; _Herpestes_, the ichneumon, in North Africa and (?) Spain; _Hyæna_, in South Europe; _Gazella_, _Oryx_, _Alcephalus_, and _Addax_, genera of antelopes in North Africa and Palestine; _Hyrax_, in Syria; and _Hystrix_, the porcupine, in South Europe. Besides these, the camel and the horse were perhaps once indigenous in the eastern parts of the sub-region; and a wild sheep (_Ovis musmon_) still inhabits Sardinia, Corsica, and the mountains of the south-east of Spain. The presence of the large feline animals--such as the lion, the leopard, the serval, and the hunting leopard--in North Africa, together with several other quadrupeds not found in Europe, have been thought by some naturalists to prove, that this district should not form part of the Palæarctic region. No doubt several Ethiopian groups and species have entered it from the south; but the bulk of its Mammalia still remains Palæarctic, although several of the species have Asiatic rather than European affinities. The _Macacus innuus_ is allied to an Asiatic rather than an African group of monkeys, and thus denotes an Oriental affinity. Ethiopian affinity is apparently shown by the three genera of antelopes, by _Herpestes_, and by _Macroscelides_; but our examination of the Miocene fauna has shown that these were probably derived from Europe originally, and do not form any part of the truly indigenous or ancient Ethiopian fauna. Against these, however, we have the occurrence in North Africa of such purely Palæarctic and non-Ethiopian genera as _Ursus_, _Meles_, _Putorius_, _Sus_, _Cervus_, _Dama_, _Capra_, _Alactaga_; together with actual European or West Asiatic species of _Canis_, _Genetta_, _Felis_, _Putorius_, _Lutra_, many bats, _Sorex_, _Crocidura_, _Crossopus_, _Hystrix_, {203}_Dipus_, _Lepus_, and _Mus_. It is admitted that, as regards every other group of animals, North Africa is Palæarctic, and the above enumeration shows that even in Mammalia, the intermixture of what are now true Ethiopian types is altogether insignificant. It must be remembered, also, that the lion inhabited Greece even in historic times, while large carnivora were contemporary with man all over Central Europe.

_Birds._--So many of the European birds migrate over large portions of the region, and so many others have a wide permanent range, that we cannot expect to find more than a few genera, consisting of one or two species, each, confined to a sub-region; and such appear to be, _Lusciniola_ and _Pyrophthalma_, genera of Sylviidæ. But many are characteristic of this, as compared with other Palæarctic sub-regions; such as, _Bradyptetus_, _Aedon_, _Dromoloea_, and _Cercomela_, among Sylviidæ; _Crateropus_ and _Malacocercus_, among Timaliidæ; _Telophonus_ among Laniidæ; _Certhilauda_ and _Mirafra_ among larks; _Pastor_ among starlings; _Upupa_, the hoopoe; _Halycon_ and _Ceryle_ among kingfishers; _Turnix_ and _Caccabis_ among Gallinæ, and the pheasant as an indigenous bird; together with _Gyps_, _Vultur_ and _Neophron_, genera of vultures. In addition to these, almost all our summer migrants spend their winter in some part of this favoured land, mostly in North Africa, together with many species of Central Europe that rarely or never visit us. It follows, that a large proportion of all the birds of Europe and Western Asia are to be found in this sub-region, as will be seen by referring to the list of the genera of the region. Palestine is one of the remote portions of this region which has been well explored by Canon Tristram, and it may be interesting to give his summary of the range of the birds. We must bear in mind that the great depression of the Dead Sea has a tropical climate, which accounts for the presence here only, of such a tropical form as the sun-bird (_Nectarinea osea_).

The total number of the birds of Palestine is 322, and of these no less than 260 are European, at once settling the question of the general affinities of the fauna. Of the remainder eleven belong to North and East Asia, four to the Red Sea, and {204}thirty-one to East Africa, while twenty-seven are peculiar to Palestine. It is evident therefore that an unusual number of East African birds have extended their range to this congenial district, but most of these are desert species and hardly true Ethiopians, and do not much interfere with the general Palæarctic character of the whole assemblage. As an illustration of how wide-spread are many of the Palæarctic forms, we may add, that seventy-nine species of land birds and fifty-five of water birds, are common to Palestine and Britain. The Oriental and Ethiopian genera _Pycnonotus_ and _Nectarinea_ are found here, while _Bessornis_ and _Dromolæa_ are characteristically Ethiopian. Almost all the other genera are Palæarctic.

Persia is another remote region generally associated with the idea of Oriental and almost tropical forms, but which yet undoubtedly belongs to the Palæarctic region. Mr. Blanford's recent collections in this country, with other interesting information, is summarised in Mr. Elwes's paper on the "Geographical Distribution of Asiatic Birds" (_Proc. Zool. Soc._ 1873, p. 647). No less than 127 species are found also in Europe, and thirty-seven others belong to European genera; seven are allied to birds of Central Asia or Siberia, and fifteen to those of North-East Africa, while only three are purely of Indian affinities. This shows a preponderance of nearly nine-tenths of Palæarctic forms, which is fully as much as can be expected in any country near the limits of a great region.

_Reptiles and Amphibia._--The climatal conditions being here more favourable to these groups, and the genera being often of limited range, we find some peculiar, and several very interesting forms. _Rhinechis_, a genus of Colubrine snakes, is found only in South Europe; _Trogonophis_, one of the Amphisbænians--curious snake-like lizards--is known only from North Africa; _Psammosaurus_, belonging to the water lizards (Varanidæ) is found in North Africa and North-West India; _Psammodromus_, a genus of Lacertidæ, is peculiar to South Europe; _Hyalosaurus_, belonging to the family Zonuridæ, is a lizard of especial interest, as it inhabits North Africa while its nearest ally is the _Ophisaurus_ or "glass snake" of North America; the family of {205}the scinks is represented by _Scincus_ found in North Africa and Arabia. Besides these _Seps_, a genus of sand lizards (Sepidæ) and _Agama_, a genus of Agamidæ, are abundant and characteristic.

Of Amphibia we have _Seiranota_, a genus of salamanders found only in Italy and Dalmatia; _Chioglossa_, in Portugal, and _Geotriton_, in Italy, belonging to the same family, are equally peculiar to the sub-region.

_Freshwater Fish._--One of the most interesting is _Tellia_, a genus of Cyprinodontidæ found only in alpine pools in the Atlas mountains. _Paraphoxinius_, found in South-East Europe, and _Chondrostoma_, in Europe and Western Asia, genera of Cyprimidæ, seem almost peculiar to this sub-region.

_Insects--Lepidoptera._--Two genera of butterflies, _Thais_ and _Doritis_, are wholly confined to this sub-region, the former ranging over all Southern Europe, the latter confined to Eastern Europe and Asia Minor. _Anthocharis_ and _Zegris_ are very characteristic of it, the latter only extending into South Russia, while _Danais_, _Charaxes_, and _Libythea_ are tropical genera unknown in other parts of Europe.

_Coleoptera._--This sub-region is very rich in many groups of Coleoptera, of which a few only can be noticed here. Among Carabidæ it possesses _Procerus_ and _Procrustes_, almost exclusively, while _Brachinus_, _Cymindis_, _Lebia_, _Graphipterus_, _Scarites_, _Chlænius_, _Calathus_, and many others, are abundant and characteristic. Among Lamellicorns--Copridæ, Glaphyridæ, Melolonthidæ, and Cetoniidæ abound. Buprestidæ are plentiful, the genera _Julodis_, _Acmæodera_, _Buprestis_, and _Sphenoptera_ being characteristic. Among Malacoderms--Cebrionidæ, Lampyridæ, and Malachiidæ abound. The Tenebrioid Heteromera are very varied and abundant, and give a character to the sub-region. The Mylabridæ, Cantharidæ, and Oedemeridæ are also characteristic. Of the immense number of Curculionidæ--_Thylacites_, _Brachycerus_, _Lixus_, and _Acalles_ may be mentioned as among the most prominent. Of Longicorns there are few genera especially characteristic, but perhaps _Prinobius_, _Purpuricenus_, _Hesperophanes_, and _Parmena_ are most so. Of the remaining families, we may mention Clythridæ, Hispidæ, and Cassididæ as being abundant.

{206}_The Mediterranean and Atlantic Islands._--The various islands of the Mediterranean are interesting to the student of geographical distribution as affording a few examples of local species of very restricted range, but as a rule they present us with exactly the same forms as those of the adjacent mainland.[6] Their peculiarities do not, therefore, properly come within the scope of this work. The islands of the Atlantic Ocean belonging to this sub-region are, from their isolated position and the various problems they suggest, of much more interest, and their natural history has been carefully studied. We shall therefore give a short account of their peculiar features.

Of the three groups of Atlantic islands belonging to this sub-region, the Canaries are nearest to the Continent, some of the islands being only about fifty miles from the coast of Africa. They are, however, separated from the mainland by a very deep channel (more than 5,000 feet), as shown on our general map. The islands extend over a length of 300 miles; they are very mountainous and wholly volcanic, and the celebrated peak of Teneriffe rises to a height of more than 12,000 feet. The small Madeira group is about 400 miles from the coast of Morocco and 600 from the southern extremity of Portugal; and there is a depth of more than 12,000 feet between it and the continent. The Azores are nearly 1,000 miles west of Lisbon. They are quite alone in mid-Atlantic, the most westerly islands being nearer Newfoundland than Europe, and are surrounded by ocean depths of from 12,000 to 18,000 feet. It will be convenient to take these islands first in order.

_Azores._--Considering the remoteness of this group from every other land, it is surprising to find as many as fifty-three species of birds inhabiting or visiting the Azores; and still more to {207}find that they are of Palæarctic genera and, with one exception, all of species found either in Europe, North Africa, Madeira, or the Canaries. The exception is a bullfinch peculiar to the islands, but closely allied to a European species. Of land birds there are twenty-two, belonging to twenty-one genera, all European. These genera are _Cerchneis_, _Buteo_, _Asio_, _Strix_, _Turdus_, _Oriolus_, _Erithacus_, _Sylvia_, _Regulus_, _Saxicola_, _Motacilla_, _Plectrophanes_, _Fringilla_, _Pyrrhula_, _Serinus_, _Sturnus_, _Picus_, _Upupa_, _Columba_, _Caccabis_, and _Coturnix_. Besides the bullfinch (_Pyrrhula_) other species show slight differences from their European allies, but not such as to render them more than varieties. The only truly indigenous mammal is a bat of a European species. Nine butterflies inhabit the Azores; eight of them are European species, one North American. Of beetles 212 have been collected, of which no less than 175 are European species; of the remainder, nineteen are found in the Canaries or Madeira, three in South America, while fourteen are peculiar to the islands.

Now these facts (for which we are indebted to Mr. Godman's _Natural History of the Azores_) are both unexpected and exceedingly instructive. In most other cases of remote Oceanic islands, a much larger proportion of the fauna is endemic, or consists of peculiar species and often of peculiar genera; as is well shown by the case of the Galapagos and Juan Fernandez, both much nearer to a continent and both containing peculiar genera and species of birds. Now we know that the cause and meaning of this difference is, that in the one case the original immigration is very remote and has never or very rarely been repeated, so that under the unchecked influence of new conditions of life the species have become modified; in the other case, either the original immigration has been recent, or if remote has been so frequently repeated that the new comers have kept up the purity of the stock, and have not allowed time for the new conditions to produce the effect we are sure they would in time produce if not counteracted. For Mr. Godman tells us that many of the birds are modified--instancing the gold-crested wren, blackcap, and rock dove--and he adds, that the {208}modification all tends in one direction--to produce a more sombre plumage, a greater strength of feet and legs, and a more robust bill. We further find, that four of the land-birds, including the oriole, snow-bunting, and hoopoe, are not resident birds, but straggle accidentally to the islands by stress of weather; and we are told that every year some fresh birds are seen after violent storms. Add to this the fact, that the number of species diminishes in the group as we go from east to west, and that the islands are subject to fierce and frequent storms blowing from every point of the compass,--and we have all the facts requisite to enable us to understand how this remote archipelago has become stocked with animal life without ever probably being much nearer to Europe than it is now. For the islands are all volcanic, the only stratified rock that occurs being believed to be of Miocene date.

_Madeira and the Canaries._--Coming next to Madeira, we find the number of genera of land birds has increased to twenty-eight, of which seventeen are identical with those of the Azores. Some of the commonest European birds--swallows, larks, sparrows, linnets, goldfinches, ravens, and partridges, are among the additions. A gold-crested warbler, _Regulus Maderensis_, and a pigeon, _Columba Trocaz_, are peculiar to Madeira.

In the Canaries we find that the birds have again very much increased, there being more than fifty genera of land birds; but the additions are wholly European in character, and almost all common European species. We find a few more peculiar species (five), while some others, including the wild canary, are common to all the Atlantic Islands or to the Canaries and Madeira. Here, too, the only indigenous mammalia are two European species of bats.

_Land Shells._--The land shells of Madeira offer us an instructive contrast to the birds of the Atlantic Islands. About fifty-six species have been found in Madeira, and forty-two in the small adjacent island of Porto Santo, but only twelve are common to both, and all or almost all are distinct from their nearest allies in Europe and North Africa. Great numbers of fossil shells are also found in deposits of the Newer Pliocene period; and {209}although these comprise many fresh species, the two faunas and that of the continent still remain almost as distinct from each other as before. It has been already stated (p. 31) that the means by which land mollusca have been carried across arms of the sea are unknown, although several modes may be suggested; but it is evidently a rare event, requiring some concurrence of favourable conditions not always present. The diversity and specialization of the forms of these animals is, therefore, easily explained by the fact, that, once introduced they have been left to multiply under the influence of a variety of local conditions, which inevitably lead, in the course of ages, to the formation of new varieties and new species.

_Coleoptera._--The beetles of Madeira and the Canaries have been so carefully collected and examined by Mr. T. V. Wollaston, and those of the Azores described and compared by Mr. Crotch, and they illustrate so many curious points in geographical distribution, that it is necessary to give some account of them. No less than 1,480 species of beetles have been obtained from the Canaries and Madeira, only 360 of which are European, the remainder being peculiar to the islands. The Canaries are inhabited by a little over 1,000 species, Madeira by about 700, while 240 are common to both; but it is believed that many of these have been introduced by man. In the Azores, 212 species have been obtained, of which 175 are European; showing, as in the birds, as closer resemblance to the European fauna than in the other islands which, although nearer to the continent, offer more shelter and are situated in a less tempestuous zone. Of the non-European species in the Azores, 19 are found also in the other groups of islands, 14 are peculiar, while 3 are American. Of the European species, 132 are found also in the other Atlantic islands, while 43 have reached the Azores only. This is interesting as showing to how great an extent the same insects reach all the islands, notwithstanding the difference of latitude and position; and it becomes of great theoretical importance, when we find how many extensive families and genera are altogether absent.

The Madeira group has been more thoroughly explored than {210}any other, and its comparatively remote situation, combined with its luxuriant vegetation, have been favourable to the development and increase of the peculiar forms which characterize all the Atlantic islands in a more or less marked degree. A consideration of some of its peculiarities will, therefore, best serve to show the bearing of the facts presented by the insect fauna of the Atlantic islands, on the general laws of distribution. The 711 species of beetles now known from the Madeira group, belong to 236 genera; and no less than 44 of these genera are not European but are peculiar to the Atlantic islands. Most of them are, however, closely allied to European genera, of which they are evidently modifications. A most curious general feature presented by the Madeiran beetles, is the total absence of many whole families and large genera abundant in South Europe. Such are the Cicindelidæ, or tiger beetles; the Melolonthidæ, or chafers; the Cetoniidæ, or rose-chafers; the Eumolpidæ and Galerucidæ, large families of Phytophagous, or leaf-eating beetles; and also the extensive groups of Elateridæ and Buprestidæ, which are each represented by but one minute species. Of extensive genera abundant in South Europe, but wholly absent in Madeira, are _Carabus_, _Rhizotrogus_, _Lampyris_, and other genera of Malacoderms; _Otiorhynchus_, _Brachycerus_, and 20 other genera of Curculionidæ, comprising more than 300 South European and North African species; _Pimelia_, _Tentyra_, _Blaps_, and 18 other genera of Heteromera, comprising about 550 species in South Europe and North Africa; and _Timarcha_, containing 44 South European and North African species.

Another most remarkable feature of the Madeiran Coleoptera is the unusual prevalence of apterous or wingless insects. This is especially the case with groups which are confined to the Atlantic islands, many of which consist wholly of wingless species; but it also affects the others, no less than twenty-two genera which are usually or sometimes winged in Europe, having only wingless species in Madeira; and even the same species which is winged in Europe becomes, in at least three cases, wingless in Madeira, without any other perceptible change having taken place. But there is another most curious fact noticed by {211}Mr. Wollaston; that those species which possess wings in Madeira, often have them rather larger than their allies in Europe. These two facts were connected by Mr. Darwin, who suggested that flying insects are much more exposed to be blown out to sea and lost, than those which do not fly (and Mr. Wollaston had himself supposed that the "stormy atmosphere" of Madeira had something to do with the matter); so that the most frequent fliers would be continually weeded out, while the more sluggish individuals, who either could not or would not fly, remained to continue the race; and this process going on from generation to generation, would, on the well-ascertained principles of selection and abortion by disuse, in time lead to the entire loss of wings by those insects to whom wings were _not a necessity_. But those whose wings were essential to their existence would be acted upon in another way. All these must fly to obtain their food or provide for their offspring, and those that flew best would be best able to battle with the storms, and keep themselves safe, and thus those with the longest and most powerful wings would be preserved. If however all the individuals of the species were too weak on the wing to resist the storms, they would soon become extinct.[7]

Now this explanation of the facts is not only simple and probable in itself, but it also serves to explain in a remarkable manner some of the peculiarities and deficiencies of the Madeiran insect fauna, in harmony with the view (supported by the distribution of the birds and land shells, and in particular by the immigrant birds and insects of the Azores) that all the insects have been derived from the continent or from other islands, by {212}immigration across the ocean, in various ways and during a long period. These deficiencies are, on the other hand, quite inconsistent with the theory (still held by some entomologists) that a land communication is absolutely necessary to account for the origin of the Madeiran fauna.

First, then, we can understand how the tiger-beetles (Cicindelidæ) are absent; since they are insects which have a short weak flight, but yet to whom flight is necessary. If a few had been blown over to Madeira, they would soon have become exterminated. The same thing applies to the Melolonthidæ, Cetoniidæ, Eumolpidæ, and Galerucidæ,--all flower and foliage-haunting insects, yet bulky and of comparatively feeble powers of flight. Again, all the large genera abundant in South Europe, which have been mentioned above as absent from Madeira, are wholly apterous (or without wings), and thus their absence is a most significant fact; for it proves that in the case of all insects of moderate size, flight was essential to their reaching the island, which could not have been the case had there been a land connection. There are, however, one or two curious exceptions to the absence of these wholly apterous European genera in Madeira, and as in each case the reason of their being exceptions can be pointed out, they are eminently exceptions that prove the rule. Two of the apterous species common to Europe and Madeira are found always in ants' nests; and as ants, when winged, fly in great swarms and are carried by the wind to great distances, they may have conveyed the minute eggs of these very small beetles. Two European species of _Blaps_ occur in Madeira, but these are house beetles, and are admitted to have been introduced by man. There are also three species of _Meloe_, of which two are European and one peculiar. These are large, sluggish, wingless insects, but they have a most extraordinary and exceptional metamorphosis, the larvae in the first state being minute active insects parasitic on bees, and thus easily conveyed across the ocean. This case is most suggestive, as it accounts for what would be otherwise a difficult anomaly. Another case, not quite so easily explained, is that of the genus _Acalles_, which is very abundant in all the Atlantic {213}islands and also occurs in South Europe, but is always apterous. It is however closely allied to another genus, _Cryptorhynchus_, which is apterous in some species, winged in others. We may therefore well suppose that the ancestors of _Acalles_ were once in the same condition, and that some of the winged forms reached Madeira, the genus having since become wholly apterous.

We may look at this curious subject in another way. The Coleoptera of Madeira may be divided into those which are found also in Europe or the other islands, and those which are peculiar to it. On the theory of introduction by accidental immigration across the sea, the latter must be the more ancient, since they have had time to become modified; while the former are comparatively recent, and their introduction may be supposed to be now going on. The peculiar influence of Madeira in aborting the wings should, therefore, have acted on the ancient and changed forms much more powerfully than on the recent and unchanged forms. On carefully comparing the two sets of insects (omitting those which have almost certainly been introduced by man) we find, that out of 263 species which have a wide range, only 14 are apterous; while the other class, consisting of 393 species, has no less than 178 apterous; or about 5 per cent in the one case, and 45 per cent in the other.[8] On the theory of a land connection as the main agent in introducing the fauna, both groups must have been introduced at or about the same time, and why one set should have lost their wings and the other not, is quite inexplicable.

Taking all these singular facts, in connection with the total absence of all truly indigenous terrestrial mammalia and reptiles from these islands--even from the extensive group of the Canaries so comparatively near to the continent, we are forced to reject the theory of a land connection as quite untenable; and this view becomes almost demonstrated by the case of the Azores, which being so much further off, and surrounded by such a vast expanse of deep ocean, could only have been {214}connected with Europe at a far remoter epoch, and ought therefore to exhibit to us a fauna composed almost entirely of peculiar forms both of birds and insects. Yet, so far from this being the case, the facts are exactly the reverse. Far more of the birds and insects are identical with those of Europe than in the other islands, and this difference is clearly traced to the more tempestuous atmosphere, which is shown to be even now annually bringing fresh immigrants (both birds and insects) to its shores. We here see nature actually at work; and if the case of Madeira rendered her mode of action probable, that of the Azores may be said to demonstrate it.

Mr. Wollaston has objected to this view that "storms and hurricanes" are somewhat rare in the latitude of Madeira and the Canaries; but this little affects the question, since the _time_ allowed for such operations is so ample. If but one very violent storm happened in a century, and ten such storms recurred before a single species of insect was introduced into Madeira, that would be more than sufficient to people it, as we now find it, with a varied fauna. But he also adds the important information that the ordinary winds blow almost uninterruptedly from the north-east, so that there would be always a chance of a little stronger wind than usual bringing insect, or larva, or egg, attached to leaves or twigs. Neither Mr. Wollaston, Mr. Crotch, Mr. A. Murray, nor any other naturalist who upholds the land-connection theory, has attempted to account for the fact of the absence of so many extensive groups of insects that ought to be present, as well as of all small mammalia and reptiles.

_Cape Verd Islands._--There is yet another group of Atlantic islands which is very little known, and which is usually considered to be altogether African--the Cape Verd Islands, situated between 300 and 400 miles west of Senegal, and a little to the south of the termination of the Sahara. The evidence that we possess as to the productions of these islands, shows that, like the preceding groups, they are truly oceanic, and have probably derived their fauna from the desert and the Canaries to the north-east of them rather than from the fertile and more truly {215}Ethiopian districts of Senegal and Gambia to the east. There is a mingling of the two faunas, but the preponderance seems to be undoubtedly with the Palæarctic rather than with the Ethiopian. I owe to Mr. R. B. Sharpe of the British Museum, a MS. list of the birds of these islands, twenty-three species in all. Of these eight are of wide distribution and may be neglected. Seven are undoubted Palæarctic species, viz.:--_Milvus ictinus_, _Sylvia atricapilla_, _S. conspicillata_, _Corvus corone_, _Passer salicarius_, _Certhilauda desertorum_, _Columba livia_. Three are peculiar species, but of Palæarctic genera and affinities, viz.:--_Calamoherpe brevipennis_, _Ammomanes cinctura_, and _Passer jagoensis_. Against this we have to set two West African species, _Estrilda cinerea_ and _Numida meleagris_, both of which were probably introduced by man; and three which are of Ethiopian genera and affinities, viz.:--_Halcyon erythrorhyncha_, closely allied to _H. semicærulea_ of Arabia and North-east Africa, and therefore almost Palæarctic; _Accipiter melanoleucus_; and _Pyrrhulauda nigriceps_, an Ethiopian form; but the same species occurs in the Canaries.

The Coleoptera of these islands have been also collected by Mr. Wollaston, and he finds that they have generally the same European character as those of the Canaries and Madeira, several of the peculiar Atlantic genera, such as _Acalles_ and _Hegeter_, occurring, while others are represented by new but closely allied genera. Out of 275 species 91 were found also in the Canaries and 81 in the Madeiran group; a wonderful amount of similarity when we consider the distance and isolation of these islands and their great diversity of climate and vegetation.

This connection of the four groups of Atlantic islands now referred to, receives further support from the occurrence of land-shells of the subgenus _Leptaxis_ in all the groups, as well as in Majorca; and by another subgenus, _Hemicycla_, being common to the Canaries and Cape Verd islands. Combining these several classes of facts, we seem justified in extending the Mediterranean sub-region to include the Cape Verd Islands.

{216}_III.--The Siberian Sub-region, or Northern Asia._

This large and comparatively little-known subdivision of the Palæarctic region, extends from the Caspian Sea to Kamschatka and Behring's Straits, a distance of about 4,000 miles; and from the shores of the Arctic Ocean to the high Himalayas of Sikhim in North Latitude 29°, on the same parallel as Delhi. To the east of the Caspian Sea and the Ural Mountains is a great extent of lowland which is continued round the northern coast, becoming narrower as it approaches the East Cape. Beyond this, in a general E.N.E. direction, rise hills and uplands, soon becoming lofty mountains, which extend in an unbroken line from the Hindu Koosh, through the Thian Shan, Altai and Yablonoi Mountains, to the Stanovoi range in the north-eastern extremity of Asia. South of this region is a great central basin, which is almost wholly desert; beyond which again is the vast plateau of Thibet, with the Kuenlun, Karakorum, and Himalayan snow-capped ranges, forming the most extensive elevated district on the globe.

The superficial aspects of this vast territory, as determined by its vegetable covering, are very striking and well contrasted. A broad tract on the northern coast, varying from 150 to 300 and even 500 miles wide, is occupied by the Tundras or barrens, where nothing grows but mosses and the dwarfest Arctic plants, and where the ground is permanently frozen to a great depth. This tract has its greatest southern extension between the rivers Obi and Yenesi, where it reaches the parallel of 60° north latitude. Next to this comes a vast extent of northern forests, mostly of conifers in the more northern and lofty situations, while deciduous trees preponderate in the southern portions and in the more sheltered valleys. The greatest extension of this forest region is north of Lake Baikal, where it is more than 1,200 miles wide. These forests extend along the mountain ranges to join those of the Hindu Koosh. South of the forests the remainder of the sub-region consists of open pasture-lands and vast intervening deserts, of which the Gobi, and those of Turkestan between the Aral and Balkash lakes, are the most {217}extensive. The former is nearly 1,000 miles long, with a width of from 200 to 350 miles, and is almost as complete a desert as the Sahara.

With very few exceptions, this vast territory is exposed to an extreme climate, inimical to animal life. All the lower parts being situated to the north, have an excessively cold winter, so that the limit of constantly frozen ground descends below the parallel of 60° north latitude. To the south, the land is greatly elevated, and the climate extremely dry. In summer the heat is excessive, while the winter is almost as severe as further north. The whole country, too, is subject to violent storms, both in summer and winter; and the rich vegetation that clothes the steppes in spring, is soon parched up and replaced by dusty plains. Under these adverse influences we cannot expect animal life to be so abundant as in those sub-regions subject to more favourable physical conditions; yet the country is so extensive and so varied, that it does actually, as we shall see, possess a very considerable and interesting fauna.

_Mammalia._--Four genera seem to be absolutely confined to this sub-region, _Nectogale_, a peculiar form of the mole family (Talpidæ); _Poephagus_, the yak, or hairy bison of Thibet; with _Procapra_ and _Pantholops_, Thibetan antelopes. Some others more especially belong here, although they just enter Europe, as _Saiga_, the Tartarian antelope; _Sminthus_, a desert rat;, and _Ellobius_, a burrowing mole-rat; while _Myospalax_, a curious rodent allied to the voles, is found only in the Altai mountains and North China; and _Moschus_, the musk-deer, is almost confined to this sub-region. Among the characteristic animals of the extreme north, are _Mustela_, and _Martes_, including the ermine and sable; _Gulo_, the glutton; _Tarandus_, the reindeer; _Myodes_, the lemming; with the lynx, arctic fox, and polar bear; and here, in the Post-pliocene epoch, ranged the hairy rhinoceros and Siberian mammoth, whose entire bodies still remain preserved in the ice-cliffs near the mouths of the great rivers. Farther south, species of wild cat, bear, wolf, deer, and pika (_Lagomys_) abound; while in the mountains we find wild goats and sheep of several species, and in the plains and deserts wild horses {218}and asses, gazelles, two species of antelopes, flying squirrels (_Pteromys_), ground squirrels (_Tamias_), marmots, of the genus _Spermophilus_, with camels and dromedaries, probably natives of the south-western part of this sub-region. The most abundant and conspicuous of the mammalia are the great herds of reindeer in the north, the wolves of the steppes, with the wild horses, goats, sheep, and antelopes of the plateaus and mountains.

Among the curiosities of this sub-region we must notice the seal, found in the inland and freshwater lake Baikal, at an elevation of about 2,000 feet above the sea. It is a species of _Callocephalus_, closely allied to, if not identical with, one inhabiting northern seas as well as the Caspian and Lake Aral. This would indicate that almost all northern Asia was depressed beneath the sea very recently; and Mr. Belt's view, of the ice during the glacial epoch having dammed up the rivers and converted much of Siberia into a vast freshwater or brackish lake, perhaps offers the best solution of the difficulty.[9]

_Plate II.--Characteristic Mammalia of Western Tartary._--Several of the most remarkable animals of the Palæarctic region inhabit Western Tartary, and are common to the European and Siberian sub-regions. We therefore choose this district for one of our illustrative plates. The large animals in the centre are the remarkable saiga antelopes (_Saiga Tartarica_), distinguished from all others by a large and fleshy proboscis-like nose, which gives them a singular appearance. They differ so much from all other antelopes that they have been formed into a distinct family by some naturalists, but are here referred to the great family Bovidæ. They inhabit the open plains from Poland to the Irtish River. On the left is the mole-rat, or sand-rat (_Spalax murinus_). This animal burrows under ground like a mole, feeding on bulbous roots. It inhabits the same country as the saiga, but extends farther south in Europe. On the right is a still more curious animal, the desman (_Myogale Muscovitica_), a long-snouted water-mole. This creature is fifteen inches long, including the tail; it burrows in the banks of streams, feeding on insects, {219}worms, and leeches; it swims well, and remains long under water, raising the tip of the snout, where the nostrils are situated, to the surface when it wants to breathe. It is thus well concealed; and this may be one use of the development of the long snout, as well as serving to follow worms into their holes in the soft earth. This species is confined to the rivers Volga and Don in Southern Russia, and the only other species known inhabits some of the valleys on the north side of the Pyrenees. In the distance are wolves, a characteristic feature of these wastes.

Plate II.

CHARACTERISTIC MAMMALIA OF WESTERN TARTARY.

_Birds._--But few genera of birds are absolutely restricted to this sub-region. _Podoces_, a curious form of starling, is the most decidedly so; _Mycerobas_ and _Pyrrhospiza_ are genera of finches confined to Thibet and the snowy Himalayas; _Leucosticte_, another genus of finches, is confined to the eastern half of the sub-region and North America; _Tetraogallus_, a large kind of partridge, ranges west to the Caucasus; _Syrrhaptes_, a form of sand-grouse, and _Lerwa_ (snow-partridge), are almost confined here, only extending into the next sub-region; as do _Grandala_, and _Calliope_, genera of warblers, _Uragus_, a finch allied to the North American cardinals, and _Crossoptilon_, a remarkable group of pheasants.

Almost all the genera of central and northern Europe are found here, and give quite a European character to the ornithology, though a considerable number of the species are different. There are a few Oriental forms, such as _Abrornis_ and _Larvivora_ (warblers); with _Ceriornis_ and _Ithaginis_, genera of pheasants, which reach the snow-line in the Himalayas and thus just enter this sub-region, but as they do not penetrate farther north, they hardly serve to modify the exclusively Palæarctic character of its ornithology.

According to Middendorf, the extreme northern Asiatic birds are the Alpine ptarmigan (_Lagopus mutus_); the snow-bunting (_Plectrophanes nivalis_); the raven, the gyrfalcon and the snowy-owl. Those which are characteristic of the barren "tundras," but which do not range so far north as the preceding are,--the willow-grouse (_Lagopus albus_); the Lapland-bunting (_Plectrophanes {220}lapponica_); the shore-lark (_Otocorys alpestris_); the sand-martin (_Cotyle riparia_), and the sea-eagle (_Haliæetus albicilla_).

Those which are more characteristic of the northern forests, and which do not pass beyond them, are--the linnet; two crossbills (_Loxia Leucoptera_ and _L. Curvirostra_); the pine grosbeak (_Pinicola enucleator_); the waxwing; the common magpie; the common swallow; the peregrine falcon; the rough-legged buzzard; and three species of owls.

Fully one-half of the land-birds of Siberia are identical with those of Europe, the remainder being mostly representative species peculiar to Northern Asia, with a few stragglers and immigrants from China and Japan or the Himalayas. A much larger proportion of the wading and aquatic families are European or Arctic, these groups having always a wider range than land birds.

_Reptiles and Amphibia._--From the nature of the country and climate these are comparatively few, but in the more temperate districts snakes and lizards seem to be not uncommon. _Halys_, a genus of Crotaline snakes, and _Phrynocephalus_, lizards of the family Agamidæ, are characteristic of these parts. _Simotes_, a snake of the family Oligodontidæ, reaches an elevation of 16,000 feet in the Himalayas, and therefore enters this sub-region.

_Insects._--_Mesapia_ and _Hypermnestra_, genera of Papilionidæ, are butterflies peculiar to this sub-region; and _Parnassius_ is as characteristic as it is of our European mountains. Carabidæ are also abundant, as will be seen by referring to the Chapter on the Distribution of Insects in the succeeding part of this work. The insects, on the whole, have a strictly European character, although a large proportion of the species are peculiar, and several new genera appear.

_IV.--Japan and North China, or the Manchurian Sub-region._

This is an interesting and very productive district, corresponding in the east to the Mediterranean sub-region in the west, or rather perhaps to all western temperate Europe. Its limits are not very well defined, but it probably includes all Japan; the Corea and Manchuria to the Amour river and to the lower {221}slopes of the Khingan and Peling mountains; and China to the Nanlin mountains south of the Yang-tse-kiang. On the coast of China the dividing line between it and the Oriental region seems to be somewhere about Foo-chow, but as there is here no natural barrier, a great intermingling of northern and southern forms takes place.

Japan is volcanic and mountainous, with a fine climate and a most luxuriant and varied vegetation. Manchuria is hilly, with a high range of mountains on the coast, and some desert tracts in the interior, but fairly wooded in many parts. Much of northern China is a vast alluvial plain, backed by hills and mountains with belts of forest, above which are the dry and barren uplands of Mongolia. We have a tolerable knowledge of China, of Japan, and of the Amoor valley, but very little of Corea and Manchuria. The recent researches of Père David in Moupin, in east Thibet, said to be between 31° and 32° north latitude, show, that the fauna of the Oriental region here advances northward along the flanks of the Yun-ling mountains (a continuation of the Himalayas); since he found at different altitudes representatives of the Indo-Chinese, Manchurian, and Siberian faunas. On the higher slopes of the Himalayas, there must be a narrow strip from about 8,000 to 11,000 feet elevation intervening between the tropical fauna of the Indo-Chinese sub-region and the almost arctic fauna of Thibet; and the animals of this zone will for the most part belong to the fauna of temperate China and Manchuria, except in the extreme west towards Cashmere, where the Mediterranean fauna will in like manner intervene. On a map of sufficiently large scale, therefore, it would be necessary to extend our present sub-region westward along the Himalayas, in a narrow strip just below the upper limits of forests. It is evident that the large number of Fringillidæ, Corvidæ, Troglodytidæ, and Paridæ, often of south Palæarctic forms, that abound in the higher Himalayas, are somewhat out of place as members of the Oriental fauna, and are equally so in that of Thibet and Siberia; but they form a natural portion of that of North China on the one side, or of South Europe on the other.

{222}_Mammalia._--This sub-region contains a number of peculiar and very interesting forms, most of which have been recently discovered by Père David in North and West China and East Thibet. The following are the peculiar genera:--_Rhinopithecus_, a sub-genus of monkeys, here classed under _Semnopithecus_; _Anurosorex_, _Scaptochirus_, _Uropsilus_ and _Scaptonyx_, new forms of Talpidæ or moles; _Æluropus_ (Æluridæ); _Nyctereutes_ (Canidæ); _Lutronectes_ (Mustelidæ); _Cricetulus_ (Muridæ); _Hydropotes_, _Moschus_, and _Elaphodus_ (Cervidæ). The _Rhinopithecus_ appears to be a permanent inhabitant of the highest forests of Moupin, in a cold climate. It has a very thick fur, as has also a new species of _Macacus_ found in the same district. North China and East Thibet seem to be very rich in Insectivora. _Scaptochirus_ is like a mole; _Uropsilus_ between the Japanese _Urotrichus_ and _Sorex_; _Scaptonyx_ between _Urotrichus_ and _Talpa_. _Æluropus_ seems to be the most remarkable mammal discovered by Père David. It is allied to the singular panda (_Ælurus fulgens_) of Nepal, but is as large as a bear, the body wholly white, with the feet, ears, and tip of the tail black. It inhabits the highest forests, and is therefore a true Palæarctic animal, as most likely is the _Ælurus_. _Nyctereutes_, a curious racoon-like dog, ranges from Canton to North China, the Amoor and Japan, and therefore seems to come best in this sub-region; _Hydropotes_ and _Lophotragus_ are small hornless deer confined to North China; _Elaphodus_, from East Thibet, is another peculiar form of deer; while the musk deer (_Moschus_) is confined to this sub-region and the last. Besides the above, the following Palæarctic genera were found by Père David in this sub-region: _Macacus_: five genera or sub-genera of bats (_Vespertilio_, _Vesperus_, _Vesperugo_, _Rhinolophus_, and _Murina_); _Erinaceus_, _Nectogale_, _Talpa_, _Crocidura_ and _Sorex_, among Insectivora; _Mustela_, _Putorius_, _Martes_, _Lutra_, _Viverra_, _Meles_, _Ælurus_, _Ursus_, _Felis_, and _Canis_, among _Carnivora_; _Hystrix_, _Arctomys_, _Myospalax_, _Spermophilus_, _Gerbillus_, _Dipus_, _Lagomys_, _Lepus_, _Sciurus_, _Pteromys_, _Arvicola_, and _Mus_, among Rodentia; _Budorcas_, _Nemorhedus_, _Antilope_, _Ovis_, _Moschus_, _Cervulus_ and _Cervus_ among Ruminants; and the wide-spread _Sus_ or wild boar. The following Oriental genera are also {223}included in Père David's list, but no doubt occur only in the lowlands and warm valleys, and can hardly be considered to belong to the Palæarctic region: _Paguma_, _Helictis_, _Arctonyx_, _Rhizomys_, _Manis_. The _Rhizomys_ from Moupin is a peculiar species of this tropical genus, but all the others inhabit Southern China.

A few additional forms occur in Japan: _Urotrichus_, a peculiar Mole, which is found also in north-west America; _Enhydra_, the sea otter of California; and the dormouse (_Myoxus_). Japan also possesses peculiar species of _Macacus_, _Talpa_, _Meles_, _Canis_, and _Sciuropterus_.

It will be seen that this sub-region is remarkably rich in Insectivora, of which it possesses ten genera; and that it has also several peculiar forms of Carnivora, Rodentia, and Ruminants.

_Birds._--To give an accurate idea of the ornithology of this sub-region is very difficult, both on account of its extreme richness and the impossibility of defining the limits between it and the Oriental region. A considerable number of genera which are well developed in the high Himalayas, and some which are peculiar to that district, have hitherto always been classed as Indian, and therefore Oriental groups; but they more properly belong to this sub-region. Many of them frequent the highest forests, or descend into the Himalayan temperate zone only in winter; and others are so intimately connected with Palæarctic species, that they can only be considered as stragglers into the border land of the Oriental region. On these principles we consider the following genera to be confined to this sub-region:--

_Grandala_, _Nemura_ (Sylviidæ); _Pterorhinus_ (Timaliidæ); _Cholornis_, _Conostoma_, _Heteromorpha_ (Panuridæ); _Cyanoptila_ (Muscicapidæ); _Eophona_ (Fringillidæ); _Dendrotreron_ (Columbidæ); _Lophophorus_, _Tetraophasis_, _Crossoptilon_, _Pucrasia_, _Thaumalea_, and _Ithaginis_ (Phasianidæ). This may be called the sub-region of Pheasants; for the above six genera, comprising sixteen species of the most magnificent birds in the world, are all confined to the temperate or cold mountainous regions of the Himalayas, Thibet, and China; and in addition we have {224}most of the species of tragopan (_Ceriornis_), and some of the true pheasants (_Phasianus_).

The most abundant and characteristic of the smaller birds are warblers, tits, and finches, of Palæarctic types; but there are also a considerable number of Oriental forms which penetrate far into the country, and mingling with the northern birds give a character to the Ornithology of this sub-region very different from that of the Mediterranean district at the western end of the region. Leaving out a large number of wide-ranging groups, this mixture of types may be best exhibited by giving lists of the more striking Palæarctic and Oriental genera which are here found intermingled.

PALÆARCTIC GENERA.

SYLVIIDÆ.
Erithacus.
Ruticilla.
Locustella.
Cyanecula.
Sylvia.
Potamodus.
Reguloides.
Regulus.
Accentor.

CINCLIDÆ.
Cinclus.

TROGLODYTIDÆ.
Troglodytidæ.

CERTHIIDÆ.
Certhia.
Sitta.
Tichodroma.

PARIDÆ.
Parus.
Lophophanes.
Acredula.

CORVIDÆ.
Fregilus.
Nucifraga.
Pica.
Cyanopica.
Garrulus.

AMPELIDÆ.
Ampelis.

FRINGILLIDÆ.
Fringilla.
Chrysomitris.
Chlorospiza.
Passer.
Coccothraustes.
Pyrrhula.
Carpodacus.
Uragus.
Loxia.
Linota.
Emberiza.

STURNIDÆ.
Sturnus.

ALAUDIDÆ.
Otocorys.

PICIDÆ.
Picoides.
Picus.
Hyopicus.
Dryocopus.

YUNGIDÆ.
Yunx.

PTEROCLIDÆ.
Syrrhaptes.

TETRAONIDÆ.
Tetrao.
Tetraogallus.
Lerwa.
Lagopus.

VULTURIDÆ.
Gypaëtus.
Vultur.

FALCONIDÆ.
Archibuteo.

ORIENTAL GENERA.

SYLVIIDÆ.
Suya.
Calliope.
Larvivora.
Tribura.
Horites.
Abrornis.
Copsychus.

TURDIDÆ.
Oreocincla.

TIMALIIDÆ.
Alcippe.
Timalia.
Pterocyclus.
Garrulax.
Trochalopteron.
Pomatorhinus. {225}
Suthora.

PANURIDÆ.
Paradoxornis.

CINCLIDÆ.
Enicurus.
Myiophonus.

TROGLODYTIDÆ.
Pnoepyga.

LIOTRICHIDÆ.
Liothrix.
Yuhina.
Pteruthius.

PYCNONOTIDÆ.
Microscelis.
Pycnonotus.
Hypsipetes.

CAMPEPHAGIDÆ.
Pericrocotus.

DICRURIDÆ.
Dicrurus.
Chibia.
Buchanga.

MUSCICAPIDÆ.
Xanthopygia.
Niltava.
Tchitrea.

CORVIDÆ.
Urocissa.

NECTARINEIDÆ.
Æthopyga.

MOTACILLIDÆ.
Nemoricola.

DICÆIDÆ.
Zosterops.

FRINGILLIDÆ.
Melophus.
Pyrgilauda.

PLOCEIDÆ.
Munia.

STURNIDÆ.
Acridotheres.
Sturnia.

PITTIDÆ.
Pitta.

PICIDÆ.
Vivia.
Yungipicus.
Gecinus.

CORACIIDÆ.
Eurystomus.

ALCEDINIDÆ.
Halcyon.
Ceryle.

UPUPIDÆ.
Upupa.

PSITTACIDÆ.
Palæornis.

COLUMBIDÆ.
Treron.
Ianthænas.
Macropygia.

PHASIANIDÆ.
Phasianus.
Ceriornis.

STRIGIDÆ.
Scops.