■*■■ .

!'■'. r " ' ■»'''•

I ' '


1 r;-$



^r /?

L* * ''*■'■

' iJ^

P *



'■ I




If *









Boston University

College of Liberal Arts Library

From the Pierce Collection






Till. WOULD „» M Km 'ATI IK'S I'UO.IX THIN „„„.,. im /' >' "; ■''■< " ; " "'" "' "■ HKlilo.XS

MTUHMMtfH IN htkiXS ... tin m'l.AN It K I









Vol. I.







I v Nrf*^ '- W ^

Tairce collection V**V Ace '-\ol*| Wjb\






The present work is an attempt to collect and summarize the existing information on the Distribution of Land Animals; and to explain the more remarkable and interesting of the facts, by means of established laws of physical and organic


The main idea, which is here worked out in some detail for the whole earth, was stated sixteen years ago in the concluding pages of a paper on the " Zoological Geography of the Malay Archipelago," which appeared in the Journal of Proceedings oj the Linnean Society for 1860 ; and again, in a paper read before the Eoyal Geographical Society in 1863, it was briefly sum- marized in the following passage :

"My object has been to show the important bearing of researches into the natural history of every part of the world, upon the study of its past history. An accurate knowledge of any groups of birds or of insects and of their geographical dis- tribution, may enable us to map out the islands and continents of a former epoch,— the amount of difference that exists be- tween the animals of adjacent districts being closely related to preceding geological changes. By the collection of such minute facts, alone, can we hope to fill up a great gap in the


past history of the earth as revealed by geology, and obtain some indications of the existence of those ancient lands which now lie buried beneath the ocean, and have left us nothing but these living records of their former existence."

The detailed study of several groups of the birds and insects collected by myself in the East, brought prominently before me some of the curious problems of Geographical Distribution; but I should hardly have ventured to treat the whole subject, had it not been for the kind encouragement of Mr. Darwin and Professor Newton, who, about six years ago, both suggested that I should undertake the task. I accordingly set to work ; but soon became discouraged by the great dearth of materials in many groups, the absence of general systematic works, and the excessive confusion that pervaded the classification. Neither was it easy to decide on any satisfactory method of treating the subject. ; During the next two years, however, several im- portant catalogues and systematic treatises appeared, which induced me to resume my work ; and during the last three years it has occupied a large portion of my time.

After much consideration, and some abortive trials, an outline plan of the book was matured ; and as this is, so far as I am aware, quite novel, it will be well to give a few of the reasons for adopting it.

Most of the previous writings on Geographical Distribution appeared to me to be unsatisfactory, because they drew their conclusions from a more or less extensive selection of facts ; and did not clearly separate groups of facts of unequal value, or those relating to groups of animals of unequal rank. As an example of what is meant, I may refer to Mr. Andrew Murray's large and valuable work on the Geographical Distribution of Mammalia, in which an immense number of coloured maps are


used to illustrate the distribution of various groups of animals. These maps are not confined to groups of any fixed rank, but are devoted to a selection of groups of various grades. Some show the range of single species of a genus as the lion, the tiger, the puma, and a species of fox ; others are devoted to sections of genera, as the true wolves ; others to genera, as the hyaenas, and the bears ; others to portions of families, as the flying squirrels, and the oxen with the bisons ; others to families, as the Mustelidse, and the Hystricidse ; and others to groups of families or to orders, as the Insectivora, and the opossums with the kangaroos. But in no one grade are all the groups treated alike. Many genera are wholly unnoticed, while several families are only treated in combination with others, or are represented by some of the more important genera.

In making these observations I by no means intend to criticise Mr. Murray's book, but merely to illustrate by an example, the method which has been hitherto employed, and which seems to me not well adapted to enable us to establish the foundations of the science of distribution on a secure basis. To do this, uniformity of treatment appeared to me essential, both as a matter of principle, and to avoid all imputation of a partial selection of facts, which may be made to prove anything. I determined, therefore, to take in succession every well-estab- lished family of terrestrial vertebrates, and to give an account of the distribution of all its component genera, as far as materials were available. Species, as such, are systematically disregarded, firstly, because they are so numerous as to be unmanageable ; and, secondly, because they represent the most recent modifica- tions of form, due to a variety of often unknown causes, and are therefore not so clearly connected with geographical changes as are the natural groups of species termed genera ; which may be considered to represent the average and more permanent


distribution of an organic type, and to be more clearly influenced by the various known or inferred changes in the organic and physical environment.

This systematic review of the distribution of families and genera, now forms the last part of my book Geographical Zoology; but it was nearly the first written, and the copious materials collected for it enabled me to determine the zoo- geographical divisions of the earth (regions and sub-regions) to be adopted. I next drew up tables of the families and genera found in each region and sub-region ; and this afforded a basis for the geographical treatment of the subject Zoological Geo- graphy— the most novel, and perhaps the most useful and generally interesting part of my work. While this was in progress I found it necessary to make a careful summary of the distribu- tion of extinct Mammalia. This was a difficult task, owing to the great uncertainty that prevails as to the affinities of many of the fossils, and my want of practical acquaintance with Palaeontology; but having carefully examined and combined the works of the best authors, I have given what I believe is the first connected sketch of the relation of extinct Mammalia to the distribution of living groups, and have arrived at some very interesting and suggestive results.

It will be observed that man is altogether omitted from the series of the animal kingdom as here given, and some ex- planation of this omission may perhaps be required. If the genus Homo had been here treated like all other genera, nothing more than the bare statement " universally distributed " could have been given ; and this would inevitably have pro- voked the criticism that it conveyed no information. If, on the other hand, I had given an outline of the distribution of the varieties or races of man, I should have departed from the plan of my work for no sufficient reason. Anthropology is a science


by itself; and it seems better to omit it altogether from a zoological work, than to treat it in a necessarily superficial manner.

The best method of illustrating a work of this kind was a matter requiring much consideration. To have had a separate coloured or shaded map for each family would have made the work too costly, as the terrestrial vertebrates alone would have required more than three hundred maps. I had also doubts about the value of this mode of illustration, as it seemed rather to attract attention to details than to favour the development of general views. T determined therefore to adopt a plan, suggested in conversation by Professor Newton ; and to have one general map, showing the regions and sub-regions, which could be referred to by means of a series of numbers. These references I give in the form of diagrammatic headings to each family ; and, when the map has become familiar, these will, I believe, convey at a glance a body of important information.

Taking advantage of the recent extension of our knowledge of the depths of the great oceans, I determined to give upon this map a summary of our knowledge of the contours of the ocean bed, by means of tints of colour increasing in intensity with the depth. Such a map, when it can be made generally accurate, will be of the greatest service in forming an estimate of the more probable changes of sea and land during the Tertiary period ; and it is on the effects of such changes that any satis- factory explanation of the facts of distribution must to a great extent depend.

Other important factors in determining the actual distribution of animals are, the zones of altitude above the sea level, and the strongly contrasted character of the surface as regards vege- tation— a primary condition for the support of animal life. I


therefore designed a series of six maps of the regions, drawn on a uniform scale, on which the belts of altitude are shown by contour-shading, while the forests, pastures, deserts, and peren- nial snows, are exhibited by means of appropriate tints of colour.

These maps will, I trust, facilitate the study of geographical distribution as a science, by showing, in some cases, an adequate cause in the nature of the terrestrial surface for the actual dis- tribution of certain groups of animals. As it is hoped they will be constantly referred to, double folding has been avoided, and they are consequently rather small ; but Mr. Stanford, and his able assistant in the map department, Mr. Bolton, have taken great care in working out the details from the latest observations; and this, combined with the clearness and the beauty of their execution, will I trust render them both interesting and in- structive.

In order to make the book more intelligible to those readers who have no special knowledge of systematic zoology, and to whom most of the names with which its pages are often crowded must necessarily be unmeaning, I give a series of twenty plates, each one illustrating at once the physical aspect and the special zoological character of some well-marked division of a region. Great care has been taken to associate in the pictures, such species only as do actually occur together in nature ; so that each plate represents a scene which is, at all events, not an impossible one. The species figured all belong to groups which are either pecu- liar to, or very characteristic of, the region whose zoology they illustrate ; and it is hoped that these pictures will of themselves serve to convey a notion of the varied types of the higher animals in their true geographical relations. The artist, Mr. J. B. Zwecker, to whose talent as a zoological draughtsman and oreat knowledge both of animal and vegetable forms we are indebted for this set of drawings, died a few weeks after he


had put the final touches to the proofs. He is known to many readers by his vigorous illustrations of the works of Sir Samuel Baker, Livingstone, and many other travellers,— but these, his last series of plates, were, at my special request, executed with a care, delicacy, and artistic finish, which his other designs seldom exhibit. It must, however, be remembered, that the figures of animals here given are not intended to show specific or generic characters for the information of the scientific zoolo- gist, but merely to give as accurate an idea as possible, of some of the more remarkable and more restricted types of beast and bird, amid the characteristic scenery of their native country ;-'- and in carrying out this object there are probably few artist who would have succeeded better than Mr. Zwecker has done.

The general arrangement of the separate parts of which the work is composed, has been, to some extent, determined by the illustrations and maps, which all more immediately belong to Part III. It was at first intended to place this part last, but as this arrangement would have brought all the illustrations into the second volume, its place was changed,— perhaps in other respects for the better, as it naturally follows Part II. Yet for persons not well acquainted with zoology, it will per- haps be advisable to read the more important articles of Part IV. (and especially the observations at the end of each order) after Part II., thus making Part III. the conclusion of the work.

Part IV. is, in fact, a book of reference, in which the distri- bution of all the families and most of the *genera of the higher animals, is given in systematic order. Part III. is treated somewhat more popularly; and, although it is necessarily crowded with scientific names (without which the inferences


and conclusions would have nothing solid to rest on), these may be omitted by the non-scientific reader, or merely noted as a certain number or proportion of peculiar generic types. Many English equivalents to family and generic names are, however, given; and, assisted by these, it is believed that any reader capable of understanding Lyell's "Principles," or Darwin's " Origin," will have no difficulty in following the main argu- ments and appreciating the chief conclusions arrived at in the present work.

To those who are more interested in facts than in theories, pie book will serve as a kind of dictionary of the geography and affinities of animals. By means of the copious Index, the native country, the systematic position, and the numerical extent of every important and well established genus of land- animal may be at once discovered ; information now scattered through hundreds of volumes.

In the difficult matters of synonymy, and the orthography of generic names, I have been guided rather by general utility than by any fixed rules. When I have taken a whole family croup from a modern author of repute, I have generally followed his nomenclature throughout. In other cases, I use the names which are to be found in a majority of modern authors, rather than follow the strict rule of priority in adopting some newly discovered appellation of early date. In orthography I have adopted all such modern emendations as seem coming into general use, and which do not lead to inconvenience ; but where the alteration is such as to completely change the pronunciation and appearance of a well-known word, I have not adopted it. I have also thought it best to preserve the initial letter of well- known and old-established names, for convenience of reference to the Indices of established works. As an example I may refer to Enicurus,—& name which has been in use nearly half a


century, and which is to be found under the letter E, in Jerdon's Birds of India, Blyth's Catalogue, Bonaparte's Conspectus, and the Proceedings of the Zoological Society of London down to 1865. Classicists now write Henicurus as the correct form ; but this seems to me one of those cases in which orthographical accuracy should give way to priority, and still more to con- venience.

In combining and arranging so much detail from such varied sources, many errors and omissions must doubtless have occurred. Owing to my residence at a distance from the scientific libraries of the metropolis, I was placed at a great disadvantage ; and I could hardly have completed the work at all, had I not been permitted to have a large number of volumes at once, from the library of the Zoological Society of London, and to keep them for months together; a privilege for which I return my best thanks to Mr. Sclater the Secretary, and to the Council.

Should my book meet with the approval of working natu- ralists, I venture to appeal to them, to assist me in rendering any future editions more complete, by sending me (to the care of my publishers) notes of any important omissions, or corrections of any misstatements of fact ; as well as copies of any of their papers or essays, and especially of any lists, catalogues, and monographs, containing information on the classification or distribution of living or extinct animals.

To the many friends who have given me information or assistance 1 beg to tender my sincere thanks. Especially am I indebted to Professor Newton, who not only read through much of my rough MSS., but was so good as to make numerous cor- rections and critical notes. These were of great value to me, as they often contained or suggested important additional matter, or pointed out systematic and orthographical inaccuracies.


Professor Flower was so good as to read over my chapters on extinct animals, and to point out several errors into which I had fallen.

Dr. Gunther gave me much valuable information on the classification of reptiles, marking on my lists the best established and most natural genera, and referring me to reliable sources of information.

I am also greatly indebted to the following gentlemen for detailed information on special subjects :

To Sir Victor Brooke, for a MS. arrangement of the genera of Bovidse, with the details of their distribution :

To Mr. Dresser, for lists of the characteristic birds of Northern and Arctic Europe :

To Dr. Hooker, for information on the colours and odours of New Zealand plants :

To Mr. Kirby, for a list of the butterflies of Chili :

To Professor Mivart, for a classification of the Batrachia, and an early proof of his article on " Apes " in the Encyclopedia Britannica :

To Mr. Salvin, for correcting my list of the birds of the Galapagos, and for other assistance :

To Mr. Sharpe, for MS. lists of the birds of Madagascar and the Cape Verd Islands:

To Canon Tristram, for a detailed arrangement of the difficult family of the warblers, Sylviidse :

To Viscount Walden, for notes on the systematic arrangement of the Pycnonotidse and Timaliidse, and for an early proof of his list of the birds of the Philippine Islands.

I also have to thank many naturalists, both in this coun- try and abroad, who have sent me copies of their papers; and I trust they will continue to favour me in the same manner.


An author may easily be mistaken in estimating his own work. I am well aware that this first outline of a great subject is, in parts, very meagre and sketchy; and, though perhaps overburthened with some kinds of detail, yet leaves many points most inadequately treated. It is therefore with some hesitation that I venture to express the hope that I have made some approach to the standard of excellence I have aimed at ; which was, that my book should bear a similar relation to the eleventh and twelfth chapters of the " Origin of Species," as Mr. Darwin's " Animals and Plants under Domestication " does to the first chapter of that work. Should it be judged worthy of such a rank, my long, and often wearisome labours, will be well repaid.

Makch, 1876.








Means of Dispersal of Mammalia (p. 10) Climate as a Limit to the Range of Mammals (p. 11) Valleys and Rivers as Barriers to Mammals (p. 12) Arms of the Sea as Barriers to Mammals ([j. 13) Ice-floes and drift-wood as aiding the Dispersal of Mammals (p. 14) Means of Dispersal of Birds (p. 15) Dis- persal of Birds by Winds (p. 16) Barriers to the Dispersal of Birds (p. 17) The Phenomena of Migration (p. 18) Migrations of Birds (p. 19) General remarks on Migration (p. 25) Means of Dispersal of Reptiles and Amphibia (p. 28)— Means of Dispersal of Fishes (p. 29)— Means of Dispersal of Mollusca (p. 30)— Means of Dispersal of Insects and the Barriers which limit their Range (p. 32) 10—34




Land and Water (p. 35)— Continental Areas (p. 36)— Recent Changes in the Con- tinental Areas (p. 38)— The Glacial Epoch as affecting the Distribution of Animals (p. 40)— Changes of Vegetation as affecting the Distribution of Ani- mals (p. 43)— Organic Changes as affecting Distribution (p. 44) . 35—49

Vol. I.— 2




Principles upon which Zoological Regions should be formed (p. 53) Which class of Animals is of most importance in determining Zoological Regions (p. 56) Various Zoological Regions proposed since 1857 (p. 58) Discussion of proposed Regions (p. 61) Reasons for adopting the Six Regions first proposed by Mr. Sclater (p. 63) Objections to the system of Circumpolar Zones (p. 67) Does the Arctic Fauna characterise an independent Region (p.68) Palsearctic Region (p. 71) Ethiopian Region (p. 73) Oriental Region (p. 75) Australian Re- gion (p. 77) Neotropical Region (p. 78) Nearctic Region (p. 79) Observations on the series of Sub-regions (p. 80) 50—82



Classification of the Mammalia (p. 85)— Classification of Birds (p. 92) Classifica- tion of Eeptiles (p. 98)— Classification of Amphibia (p. 100) Classification of Fishes (p. 101)— Classification of Insects (p. 102) Classification of Mollusca (P- 104) 83—104




Historic and Post-pliocene Period (p. 110) Pliocene Period (p. 112) General Conclusions as to the Pliocene and Post-pliocene Faunas of Europe (p. 113)— Miocene Period (p. 114) Extinct Animals of Greece (p. 115) Miocene Fauna of Central and Western Europe (p. 117) Upper Miocene Deposits of India (p. 121) General Observations on the Miocene Faunas of Europe and Asia (p. 123)— Eocene Period (p. 124) General Considerations on the Extinct Mammalian Fauna of Europe (p. 126) 107 128




North America— Post-pliocene Period (p. 129)— Remarks on the Post-pliocene Fauna of North America (p. 130)— Tertiary Period (p. 132)— Primates (p. 32) Insectivora (p. 133)— Carnivora (p. 134)— Ungulata (p. 135)— Proboscidea (p.138)— Tillodontia (p. 139)— Eodentia (p. 140)— General Relations of the Ex- tinct Tertiary Mammalia of North America and Europe (p. 140)- South Ame- rica (p. 143)— Fauna of the Brazilian Caves (p. 143) Pliocene Period of Tem- perate South America (p. 146)— Pliocene Mammalia of the Antilles (p. 148) Eocene Fauna of South America (p. 148)— General Remarks on the Extinct Mammalian Fauna of the Old and New Worlds (p. ] 48)— The Birth-place anc1 Migrations of some Mammalian Families and Genera (p. 153) . 129—156



Extinct Mammalia of Australia (p. 157)— Mammalian Remains of the Secondary Formations (p. 159)— Extinct Birds (p. 160)— Pahearctic Region and North India (p. 161)— North America (p. 163)— South America, Madagascar, New Zealand (p. 164)— Extinct Tertiary Reptiles (p. 165)— Antiquity of the Genera of Insects (p. 166)— Antiquity of the Genera of Land and Fresh-water Shells (p. 168) 157-170





Order of succession of the Regions (p. 173)— Cosmopolitan Groups (p. 175) Tables of Distributions of Families and Genera (p. 177) . . 173—179




Zoological Characteristics of the Palsearctic Region (p. 181) Summary of Palse- arctic Vertebrata (p. 186)— Insects (p. 1 87)— Land-shells (p. 190)— The Palse- arctic Sub-regions (p. 190) Central and Northern Europe (p. 191) North European Islands (p. 197) Mediterranean Sub-region (p. 199) The Mediter- ranean and Atlantic Islands (p. 206) —The Siberian Sub-region, or Northern Asia (p. 216) Japan and North China, or the Manchurian Sub-region (p. 220) Birds (p. 223) Insects (p. 227) Eemarks on the General Character of the Fauna of Japan (p. 230) General Conclusions as to the Fauna of the Palse- arctic Region (p. 231) Table I. Families of Animals inhabiting the Palse- arctic Region (p. 234) Table II. List of the Genera of Terrestrial Mammalia and Birds of the Palsearctic Region (p. 239) .... 181—250



Zoological Characteristics of the Ethiopian Region (p. 252) Summary of Ethio- pian Vertebrates (p. 255)— The Ethiopian Sub-regions (p. 258)— The East African Sub-region, or Central and East Africa (p. 258) The West African Sub-region (p. 262) Islands of the West African Sub-region (p. 265) South African Sub-region (p. 266)— Atlantic Islands of the Ethiopian Region ; St. Helena (p. 269) Tristan dAcunha (p. 271) Madagascar and the Mascarene Islands, or the Malagasy Sub-region (p. 272) The Mascarene Islands (p. 280) Extinct Fauna of the Mascarene Islands and Madagascar (p. 282) General Remarks on the Insect Fauna of Madagascar (p. 284)— On the probable Past History of the Ethiopian Region (p. 285) Table I. Families of Animals inhabiting the Ethiopian Region (p. 294) Table II. List of Genera of Ter- restrial Mammalia and Birds of the Ethiopian Region (p. 300) . 251 313



Zoological Characteristics of the Oriental Region (p; 315) Summary of Oriental Vertebrata (p. 318) The Oriental Sub-regions (p. 321) Hindostan, or Indian Sub-region (p. 321) Range of the Genera of Mammalia which inhabit the Sub- region of Hindostan (p. 322) Oriental, Palsearctic, and Ethiopian Genera of Birds in Central India (p. 224) Sub-region of Ceylon and South India (p-. 326) The Past History of Ceylon and South India, as indicated by its Fauna (p. 328) Himalayan or Indo-Chinese Sub-region (p. 329) Islands of the


Indo-Chinese Sub-region (p. 333)— Indo-Malaya, or the Malayan Sub-region (p. 334)— Malayan Insects (p. 341)— The Zoological Relations of the several Islands of the Indo-Malay Sub-region (p. 345)— Philippine Islands (p. 345)— Java (p. 349)— Malacca, Sumatra, and Borneo (p. 353)— Probable recent Geo- graphical Changes in the Indo-Malay Islands (p. 357)— Probable Origin of the Malayan Fauna (p. 359)— Concluding Remarks on the Oriental Region (p. 362) Table I. Families of Animals inhabiting the Oriental Region (p. 365)— Table II. Genera of Terrestrial Mammalia and Birds in the Oriental Re- gion (p. 371) 314-386



General Zoological Characteristics of the Australian Region (p. 390) Summary of the Australian Vertebrata (p. 397) Supposed Land-connection between Australia and South America (p. 398)— Insects (p. 403)— Land shells (p. 407) Australian Sub-regions (p. 408) Austro-Malayan Sub-region (p. 409)— Papua, or the New Guinea Group (p. 409) The Moluccas (p. 417)— Insects Peculiarities of the Moluccan Fauna (p. 420)— Timor Group (p. 422)— Celebes Group (p. 426) Origin of the Fauna of Celebes (p. 436)— Australia and Tasmania, or the Australian Sub-region (p. 438) The Pacific Islands, or Polynesian Sub-region (p. 442) Fiji, Tonga, and Samoa Islands (p. 443) Society and Marquesas Islands (p. 443) Ladrone and Caroline Islands (p. 444) New Caledonia and the New Hebrides (p. 444)— Sandwich Islands (p. 445) Reptiles of the Polynesian Sub-region (p. 448) New Zealand Sub-region (p. 449) Islets of the New Zealand Sub-region (p. 453) Reptiles, Amphibia, and Fresh-water Fishes (p. 456) Insects (p. 457) The Ancient Fauna of New Zealand (p. 459) The Origin of the New Zealand Fauna (p. 459)— Causes of the Poverty of Insect-life in New Zealand : its Influence on the Character of the Flora (p. 462) Concluding Remarks on the Early History of the Austra- lian Region (p. 464)— Table I. Families of Animals inhabiting the Australian Region (p. 468) Table II. Genera of Terrestrial Mammalia and Birds of the Australian Region (p. 473) 387—485

Index to Vol. I 489-503


1. Map of the World, showing the Zoo-Geographical Regions and the

contour of the Ocean-bed Frontispiece

To face page

2. Map of the Pahearctic Region . . . . . . .181

3. Plate I. The Alps of Central Europe with Characteristic Animals 195

4. Plate II. Characteristic Mammalia of Western Tartary . . . 218

5. Plate III. Characteristic Animals of North China .... 226

6. Map of the Ethiopian Region 251

7. Plate IV. Characteristic Animals of East Africa . ... 261

8. Plate V. Scene in West Africa with Characteristic Animals . . 264

9. Plate VI. Scene in Madagascar with Characteristic Animals . . 278

10. Map of the Oriental Region 315

11. Plate VII. Scene in Nepaul with Characteristic Animals . . . 331

12. Plate VIII. A Forest in Borneo with Characteristic Mammalia . . 337

13. Plate IX. A Malacca Forest with some of its Peculiar Birds . . 340

14. Map of the Australian Region 387

15. Plate X. Scene in New Guinea with Characteristic Animals . . 415

16. Plate XI. The Characteristic Mammalia of Tasmania . . 439

17. Plate XII. The Plains of New South Wales with Characteristic Ani-

mals 442

18. Plate XIII. Scene in New Zealand with some of its Remarkable Birds 455







It is a fact within the experience of most persons, that the various species of animals are not uniformly dispersed over the surface of the country. If we have a tolerable acquaintance with any district, be it a parish, a county, or a larger extent of territory, we soon become aware that each well-marked portion of it has some peculiarities in its animal productions. If we want to find certain birds or certain insects, we have not only to choose the right season but to go to the right place. If we travel beyond our district in various directions we shall almost certainly meet with something new to us ; some species which we were accustomed to see almost daily will disappear, others' which we have never seen before will make their appearance. If we go very far, so as to be able to measure our journey by degrees of latitude and longitude and to perceive important changes of climate and vegetation, the differences in the forms of animal life will become greater ; till at length we shall come to a country where almost everything will be new, all the familiar creatures of our own district being replaced by others more or less differing from them.

If we have been observant during our several journeys, and have combined and compared the facts we have collected, it will become apparent that the change we have witnessed has been of two distinct kinds. In our own and immediately surround- ing districts, particular species appeared and disappeared because


the soil, the aspect, or the vegetation, was adapted to them or the reverse. The marshes, the heaths, the woods and forests, the chalky downs, the rocky mountains, had each their peculiar inhabitants, which reappeared again and again as we came to tracts of country suitable for them. But as we got further away we began to find that localities very similar to those we had left behind were inhabited by a somewhat different set of species; and this difference increased with distance, notwithstanding that almost identical external conditions might be often met with. The first class of changes is that of stations ; the second that of habitats. The one is a local, the other a geograiihical phenomenon. The whole area over which a particular animal is found may consist of any number of stations, but rarely of more than one habitat. Stations, however, are often so extensive as to include the entire range of many species. Such are the great seas and oceans, the Siberian or the Amazonian forests, the North African deserts, the Andean or the Himalayan highlands.

There is yet another difference in the nature of the change we have been considering. The new animals which we meet with as we travel in any direction from our starting point, are some of them very much like those we have left behind us, and can be at once referred to familiar types ; while others are altogether unlike anything we have seen at home. When we reach the Alps we find another kind of squirrel, in South- ern Italy a distinct mole, in Southern Europe fresh warblers and unfamiliar buntings. We meet also with totally new forms ; as the glutton and the snowy owl in Northern, the genet and the hoopoe in Southern, and the saiga antelope and collared pratincole in Eastern Europe. The first series are examples of what are termed representative species, the second of distinct groups or types of animals. The one represents a comparatively recent modification, and an origin in or near the locality where it occurs ; the other is a result of very ancient changes both organic and inorganic, and is connected with some of the most curious and difficult of the problems we shall have to discuss.


Having thus defined our subject, let us glance at the opinions that have generally prevailed as to the nature and causes of the phenomena presented by the geographical distribution of animals.

It was long thought, and is still a popular notion, that the manner in which the various kinds of animals are dispersed over the globe is almost wholly due to diversities of climate and of vegetation. There is indeed much to favour this belief. The arctic regions are strongly characterised by their white bears and foxes, their reindeer, ermine, and walruses, their white ptarmigan, owls, and falcons ; the temperate zone has its foxes and wolves, its rabbits, sheep, beavers, and marmots, its sparrows and its song birds ; while tropical regions alone produce apes and elephants, parrots and peacocks, and a thousand strange quadru- peds and brilliant birds which are found nowhere in the cooler regions. So the camel, the gazelle and the ostrich live in the desert ; the bison on the prairie ; the tapir, the deer, and the jaguar in forests. Mountains and marshes, plains and rocky precipices, have each their animal inhabitants ;• and it might well be thought, in the absence of accurate inquiry, that these and other differences would sufficiently explain why most of the regions and countries into which the earth is popularly divided should have certain animals peculiar to them and should want others which are elsewhere abundant.

A more detailed and accurate knowledge of the productions of different portions of the earth soon showed that this explanation was quite insufficient ; for it was found that countries exceed- ingly similar in climate and all physical features may yet have very distinct animal populations. The equatorial parts of Africa and South America, for example, are very similar in climate and are both covered with luxuriant forests, yet their animal life is widely different; elephants, apes, leopards, guinea-fowls and touracos in the one, are replaced by tapirs, prehensile- tailed monkeys, jaguars, curassows and toucans in the other. Again, parts of South Africa and Australia are wonderfully similar in their soil and climate ; yet one has lions, antelopes, zebras and giraffes ; the other only kangaroos, wombats, phalan-


gers and mice. In like manner parts of North America and Europe are very similar in all essentials of soil climate and vegetation, yet the former has racoons, opossums, and humming- birds ; while the latter possesses moles, hedgehogs and true fly- catchers. Equally striking are the facts presented by the distribution of many large and important groups of animals. Marsupials (opossums, phalangers &c.) are found from temperate Van Diemen's land to the tropical islands of New Guinea and Celebes, and in America from Chili to Virginia. No crows exist in South America, while they inhabit every other part of the world, not excepting Australia. Antelopes are found only in Africa and Asia ; the sloths only in South America ; the true lemurs are confined to Madagascar, and the birds-of-paradise to New Guinea.

If we examine more closely the distribution of animals in any extensive region, we find that different, though closely allied species, are often found on the opposite sides of any considerable barrier to their migration. Thus, on the two sides of the Andes and Eocky Mountains in America, almost all the mammalia, birds, and insects are of distinct species. To a less extent, the Alps and Pyrenees form a similar barrier, and even great rivers and river plains, as those of the Amazon and Ganges, separate more or less distinct groups of animals. Arms of the sea are still more effective, if they are permanent ; a circumstance in some measure indicated by their depth. Thus islands far away from land almost always have very peculiar animals found nowhere else ; as is strikingly the case in Madagascar and New Zealand, and to a less degree in the West India islands. But shallow straits, like the English Channel or the Straits of Malacca, are not found to have the same effect, the animals being nearly or quite identical on their opposite shores. A change of climate or a change of vegetation may form an equally effective barrier to migration. Many tropical and polar animals are pretty accu- rately limited by certain isothermal lines ; and the limits of the great forests in most parts of the world strictly determine the ranges of many species.

Naturalists have now arrived at the conclusion, that by some


slow process of development or transmutation, all animals have been produced from those which preceded them ; and the old notion that every species was specially created as they now exist, at a particular time and in a particular spot, is abandoned as opposed to many striking facts, and unsupported by any evidence. This modification of animal forms took place very slowly, so that the historical period of three or four thousand years has hardly produced any perceptible change in a single species. Even the time since the last glacial epoch, which on the very lowest estimate must be from 50,000 to 100,000 years, has only served to modify a few of the higher animals into very slightly different species. The changes of the forms of animals appear to have accompanied, and perhaps to have depended on, changes of physical geography, of climate, or of vegetation; since it is evident that an animal which is well adapted to one condition of things will require to be slightly changed in con- stitution or habits, and therefore generally in form, structure, or colour, in order to be equally well adapted to a changed condition of surrounding circumstances. Animals multiply so rapidly, that we may consider them as continually trying to extend their range ; and thus any new land raised above the sea by geological causes becomes immediately peopled by a crowd of competing inhabitants, the strongest and best adapted of which alone succeed in maintaining their position.

If we keep in view these facts that the minor features of the earth's surface are everywhere slowly changing ; that the forms, and structure, and habits of all living things are also slowly changing ; while the great features of the earth, the continents, and oceans, and loftiest mountain ranges, only change after very long intervals and with extreme slowness ; we must see that the present distribution of animals upon the several parts of the earth's surface is the final product of all these wonderful revolutions in organic and inorganic nature. The greatest and most radical differences in the productions of any part of the globe must be dependent on isolation by the most effectual and most permanent barriers. That ocean which has remained broadest and deepest from the most remote geological epochs


will separate countries the productions of which most widely and radically differ; while the most recently-depressed seas, or the last-formed mountain ranges, will separate countries the productions of which are almost or quite identical. It will be evident, therefore, that the study of the distribution of animals and plants may add greatly to our knowledge of the past history of our globe. It may reveal to us, in a