The Geographical Distribution of Animals, Volume 1

Chapter IX: As a matter of convenience, and for other reasons adduced in

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the same chapter, the detailed exposition of the geographical distribution of the animals of the several regions in Part III. commences with the Palæarctic and terminates with the Nearctic region.

_Objections to the system of Circumpolar Zones._--Mr. Allen's system of "realms" founded on climatic zones (given at p. 61), having recently appeared in an ornithological work of considerable detail and research, calls for a few remarks. The author continually refers to the "_law of the distribution of life in circumpolar zones_," as if it were one generally accepted and that admits of no dispute. But this supposed "law" only applies to the smallest details of distribution--to the range and increasing or decreasing numbers of _species_ as we pass from north to south, or the reverse; while it has little bearing on the great features of zoological geography--the limitation of groups of _genera_ and _families_ to certain areas. It is analogous to the "_law of adaptation_" in the organisation of animals, by which members of various groups are suited for an aerial, an aquatic, a desert, or an arboreal life; are herbivorous, carnivorous, or insectivorous; are fitted to live underground, or in fresh waters, or on polar ice. It was once thought that these adaptive peculiarities were suitable foundations for a classification,--that whales were fishes, and bats birds; and even to this day there are naturalists who cannot recognise the essential diversity of structure in such groups as swifts and swallows, sun-birds and humming-birds, under the superficial disguise caused by adaptation to a similar mode of life. The application of Mr. Allen's principle leads to equally erroneous results, as may be well seen by considering his separation of "the southern third of Australia" to unite it with New Zealand as one of his secondary zoological divisions. If there is one country in the world whose fauna is strictly homogeneous, that country is Australia; while New Guinea on the one hand, and New Zealand on the other, are as sharply differentiated from Australia as any adjacent parts of the same primary zoological division can possibly be. Yet the "_law of circumpolar distribution_" leads to the division of {68}Australia by an arbitrary east and west line, and a union of the northern two-thirds with New Guinea, the southern third with New Zealand. Hardly less unnatural is the supposed equivalence of South Africa (the African temperate realm) to all tropical Africa and Asia, including Madagascar (the Indo-African tropical realm). South Africa has, it is true, some striking peculiarities; but they are absolutely unimportant as compared with the great and radical differences between tropical Africa and tropical Asia. On these examples we may fairly rest our rejection of Mr. Allen's scheme.

We must however say a few words on the zoo-geographical nomenclature proposed in the same paper, which seems also very objectionable. The following terms are proposed: _realm_, _region_, _province_, _district_, _fauna and flora_; the first being the highest, the last the lowest and smallest sub-division. Considering that most of these terms have been used in very different senses already, and that no means of settling their equivalence in different parts of the globe has been even suggested, such a complex system must lead to endless confusion. Until the whole subject is far better known and its first principles agreed upon, the simpler and the fewer the terms employed the better; and as "region" was employed for the primary divisions by Mr. Sclater, eighteen years ago, and again by Mr. Andrew Murray, in his Geographical Distribution of Mammals; nothing but obscurity can result from each writer using some new, and doubtfully better, term. For the sub-divisions of the regions no advantage is gained by the use of a distinct term--"province"--which has been used (by Swainson) for the primary divisions, and which does not itself tell you what rank it holds; whereas the term "sub-region" speaks for itself as being unmistakably next in subordination to region, and this clearness of meaning gives it the preference over any independent term. As to minor named sub-divisions, they seem at present uncalled for; and till the greater divisions are themselves generally agreed on, it seems better to adopt no technical names for what must, for a long time to come, be indeterminate.

_Does the Arctic Fauna characterize an independent {69}Region._--The proposal to consider the Arctic regions as constituting one of the primary zoological divisions of the globe, has been advocated by many naturalists. Professor Huxley seems to consider it advisable, and Mr. Allen unhesitatingly adopts it, as well as an "antarctic" region to balance it in the southern hemisphere. The reason why an "Arctic Region" finds no place in this work may therefore be here stated.

No species or group of animals can properly be classed as "arctic," which does not exclusively inhabit or greatly preponderate in arctic lands. For the purpose of establishing the need of an "arctic" zoological region, we should consider chiefly such groups as are circumpolar as well as arctic; because, if they are confined to, or greatly preponderate in, either the eastern or western hemispheres, they can be at once allocated to the Nearctic or Palæarctic regions, and can therefore afford no justification for establishing a new primary division of the globe.

Thus restricted, only three genera of land mammalia are truly arctic: _Gulo_, _Myodes_, and _Rangifer_. Two species of widely dispersed genera are also exclusively arctic, _Ursus maritimus_ and _Vulpes lagopus_.

Exclusively arctic birds are not much more numerous. Of land birds there are only three genera (each consisting of but a single species), _Pinicola_, _Nyctea_, and _Surnia_. _Lagopus_ is circumpolar, but the genus has too wide an extension in the temperate zone to be considered arctic. Among aquatic birds we have the genus of ducks, _Somateria_; three genera of Uriidæ, _Uria_, _Catarractes_, and _Mergulus_; and the small family Alcidæ, consisting of the genera _Alca_ and _Fratercula_. Our total then is, three genera of mammalia, three of land, and six of aquatic birds, including one peculiar family.

In the southern hemisphere there is only the single genus _Aptenodytes_ that can be classed as antarctic; and even that is more properly south temperate.

In dealing with this arctic fauna we have two courses open to us; we must either group them with the other species and genera which are common to the two northern regions, or we {70}must form a separate primary region for them. As a matter of convenience the former plan seems the best; and it is that which is in accordance with our treatment of other intermediate tracts which contain special forms of life. The great desert zone, extending from the Atlantic shores of the Sahara across Arabia to Central Asia, is a connecting link between the Palæarctic, Ethiopian, and Oriental regions, and contains a number of "desert" forms wholly or almost wholly restricted to it; but the attempt to define it as a separate region would introduce difficulty and confusion. Neither to the "desert" nor to the "arctic" regions could any defined limits, either geographical or zoological, be placed; and the attempt to determine what species or genera should be allotted to them would prove an insoluble problem. The reason perhaps is, that both are essentially unstable, to a much greater extent than those great masses of land with more or less defined barriers, which constitute our six regions. The Arctic Zone has been, within a recent geological period, both vastly more extensive and vastly less extensive than it is at present. At a not distant epoch it extended over half of Europe and of North America. At an earlier date it appears to have vanished altogether; since a luxuriant vegetation of tall deciduous trees and broad-leaved evergreens flourished within ten degrees of the Pole! The great deserts have not improbably been equally fluctuating; hence neither the one nor the other can present that marked individuality in their forms of life, which seems to have arisen only when extensive tracts of land have retained some considerable stability both of surface and climatal conditions, during periods sufficient for the development and co-adaptation of their several assemblages of plants and animals.

We must also consider that there is no geographical difficulty in dividing the Arctic Zone between the two northern regions. The only debateable lands, Greenland and Iceland, are generally admitted to belong respectively to America and Europe. Neither is there any zoological difficulty; for the land mammalia and birds are on the whole wonderfully restricted to their respective regions even in high latitudes; and the aquatic forms {71}are, for our present purpose, of much less importance. As a primary division the "Arctic region" would be out of all proportion to the other six, whether as regards its few peculiar types or the limited number of forms and species actually inhabiting it; but it comes in well as a connecting link between two regions, where the peculiar forms of both are specially modified; and is in this respect quite analogous to the great desert zone above referred to.

I now proceed to characterize briefly the six regions adopted in the present work, together with the sub-regions into which they may be most conveniently and naturally divided, as shown in our general map.

_Palæarctic Region._--This very extensive region comprises all temperate Europe and Asia, from Iceland to Behring's Straits and from the Azores to Japan. Its southern boundary is somewhat indefinite, but it seems advisable to comprise in it all the extra-tropical part of the Sahara and Arabia, and all Persia, Cabul, and Beloochistan to the Indus. It comes down to a little below the upper limit of forests in the Himalayas, and includes the larger northern half of China, not quite so far down the coast as Amoy. It has been said that this region differs from the Oriental by negative characters only; a host of tropical families and genera being absent, while there is little or nothing but peculiar species to characterize it absolutely. This however is not true. The Palæarctic region is well characterized by possessing 3 families of vertebrata peculiar to it, as well as 35 peculiar genera of mammalia, and 57 of birds, constituting about one-third of the total number it possesses. These are amply sufficient to characterize a region positively; but we must also consider the absence of many important groups of the Oriental, Ethiopian, and Nearctic regions; and we shall then find, that taking positive and negative characters together, and making some allowance for the necessary poverty of a temperate as compared with tropical regions, the Palæarctic is almost as strongly marked and well defined as any other.

_Sub-divisions of the Palæarctic Region._--These are by no means {72}so clearly indicated as in some of the other regions, and they are adopted more for convenience than because they are very natural or strongly marked.

The first, or European sub-region, comprises Central and Northern Europe as far South as the Pyrenees, the Maritime and Dinaric Alps, the Balkan mountains, the Black Sea, and the Caucasus. On the east the Caspian sea and the Ural mountains seem the most obvious limit; but it is doubtful if they form the actual boundary, which is perhaps better marked by the valley of the Irtish, where a pre-glacial sea almost certainly connected the Aral and Caspian seas with the Arctic ocean, and formed an effective barrier which must still, to some extent, influence the distribution of animals.

The next, or Mediterranean sub-region, comprises South Europe, North Africa with the extra-tropical portion of the Sahara, and Egypt to about the first or second cataracts; and eastward through Asia Minor, Persia, and Cabul, to the deserts of the Indus.

The third, or Siberian sub-region, consists of all north and central Asia north of Herat, as far as the eastern limits of the great desert plateau of Mongolia, and southward to about the upper limit of trees on the Himalayas.

The fourth, or Manchurian sub-region, consists of Japan and North China with the lower valley of the Amoor; and it should probably be extended westward in a narrow strip along the Himalayas, embracing about 1,000 or 2,000 feet of vertical distance below the upper limit of trees, till it meets an eastern extension of the Mediterranean sub-region a little beyond Simla. These extensions are necessary to avoid passing from the Oriental region, which is essentially tropical, directly to the Siberian sub-region, which has an extreme northern character; whereas the Mediterranean and Manchurian sub-regions are more temperate in climate. It will be found that between the upper limit of most of the typical Oriental groups and the Thibetan or Siberian fauna, there is a zone in which many forms occur common to temperate China. This is especially the case among the pheasants and finches.

{73}_Ethiopian Region._--The limits of this region have been indicated by the definition of the Palæarctic region. Besides Africa south of the tropic of Cancer, and its islands, it comprises the southern half of Arabia.

This region has been said to be identical in the main characters of its mammalian fauna with the Oriental region, and has therefore been united with it by Mr. A. Murray. Most important differences have however been overlooked, as the following summary of the peculiarities of the Ethiopian region will, I think, show.

It possesses 22 peculiar families of vertebrates; 90 peculiar genera of mammalia, being two-thirds of its whole number; and 179 peculiar genera of birds, being three-fifths of all it possesses. It is further characterized by the absence of several families and genera which range over the whole northern hemisphere, details of which will be found in the chapter treating of the region. There are, it is true, many points of resemblance, not to be wondered at between two tropical regions in the same hemisphere, and which have evidently been at one time more nearly connected, both by intervening lands and by a different condition of the lands that even now connect them. But these resemblances only render the differences more remarkable; since they show that there has been an ancient and long-continued separation of the two regions, developing a distinct fauna in each, and establishing marked specialities which the temporary intercommunication and immigration has not sufficed to remove. The entire absence of such wide-spread groups as bears and deer, from a country many parts of which are well adapted to them, and in close proximity to regions where they abound, would alone mark out the Ethiopian region as one of the primary divisions of the earth, even if it possessed a less number than it actually does of peculiar family and generic groups.

_Sub-divisions of the Ethiopian Region._--The African continent south of the tropic of Cancer is more homogeneous in its prominent and superficial zoological features than most of the other regions, but there are nevertheless important and {74}deep-seated local peculiarities. Two portions can be marked off as possessing many peculiar forms; the luxuriant forest district of equatorial West Africa, and the southern extremity or Cape district. The remaining portion has no well-marked divisions, and a large proportion of its animal forms range over it from Nubia and Abyssinia, to Senegal on the one side and to the Zambesi on the other; this forms our first or East-African sub-region.

The second, or West African sub-region extends along the coast from Senegal to Angola, and inland to the sources of the Shary and the Congo.

The third, or South African sub-region, comprises the Cape Colony and Natal, and is roughly limited by a line from Delagoa Bay to Walvish Bay.

The fourth, or Malagasy sub-region, consists of Madagascar and the adjacent islands, from Rodriguez to the Seychelles; and this differs so remarkably from the continent that it has been proposed to form a distinct primary region for its reception. Its productions are indeed highly interesting; since it possesses 3 families, and 2 sub-families of mammals peculiar to itself, while almost all its genera are peculiar. Of these a few show Oriental or Ethiopian affinities, but the remainder are quite isolated. Turning to other classes of animals, we find that the birds are almost as remarkable; but, as might be expected, a larger number of genera are common to surrounding countries. More than 30 genera are altogether peculiar, and some of these are so isolated as to require to be classed in separate families or sub-families. The African affinity is however here more strongly shown by the considerable number (13) of peculiar Ethiopian genera which in Madagascar have representative species. There can be no doubt therefore about Madagascar being more nearly related to the Ethiopian than to any other region; but its peculiarities are so great, that, were it not for its small size and the limited extent of its fauna, its claim to rank as a separate region might not seem unreasonable. It is true that it is not poorer in mammals than Australia; but that country is far more isolated, and cannot be so decidedly and {75}naturally associated with any other region as Madagascar can be with the Ethiopian. It is therefore the better and more natural course to keep it as a sub-region; the peculiarities it exhibits being of exactly the same kind as those presented by the Antilles, by New Zealand, and even by Celebes and Ceylon, but in a much greater degree.

_Oriental Region._--On account of the numerous objections that have been made to naming a region from the least characteristic portion of it, and not thinking "Malayan," proposed by Mr. Blanford, a good term, (as it has a very circumscribed and definite meaning, and especially because the "Malay" archipelago is half of it in the Australian region,) I propose to use the word "Oriental" instead of "Indian," as being geographically applicable to the whole of the countries included in the region and to very few beyond it; as being euphonious, and as being free from all confusion with terms already used in zoological geography. I trust therefore that it may meet with general acceptance.

This small, compact, but rich and varied region, consists of all India and China from the limits of the Palæarctic region; all the Malay peninsula and islands as far east as Java and Baly, Borneo and the Philippine Islands; and Formosa. It is positively characterized by possessing 12 peculiar families of vertebrata; by 55 genera of land mammalia, and 165 genera of land birds, altogether confined to it; these peculiar genera forming in each case about one half of the total number it possesses.

_Sub-divisions of the Oriental region._--First we have the Indian sub-region, consisting of Central India from the foot of the Himalayas in the west, and south of the Ganges to the east, as far as a line drawn from Goa curving south and up to the Kistna river; this is the portion which has most affinity with Africa.

The second, or Ceylonese sub-region, consists of the southern extremity of India with Ceylon; this is a mountainous forest region, and possesses several peculiar forms as well as some Malayan types not found in the first sub-region.

{76}Next we have the Indo-Chinese sub-region, comprising South China and Burmah, extending westward along the Himalayan range to an altitude of about 9,000 or 10,000 feet, and southward to Tavoy or Tenasserim.

The last is the Indo-Malayan sub-region, comprising the Peninsula of Malacca and the Malay Islands to Baly, Borneo, and the Philippines.

On account of the absence from the first sub-region of many of the forms most characteristic of the other three, and the number of families and genera of mammalia and birds which occur in it and also in Africa, it has been thought by some naturalists that this part of India has at least an equal claim to be classed as a part of the Ethiopian region. This question will be found fully discussed in Chapter XII. devoted to the Oriental region, where it is shown that the African affinity is far less than has been represented, and that in all its essential features Central India is wholly Oriental in its fauna.

Before leaving this region a few words may be said about Lemuria, a name proposed by Mr. Sclater for the site of a supposed submerged continent extending from Madagascar to Ceylon and Sumatra, in which the Lemuroid type of animals was developed. This is undoubtedly a legitimate and highly probable supposition, and it is an example of the way in which a study of the geographical distribution of animals may enable us to reconstruct the geography of a bygone age. But we must not, as Mr. Blyth proposed, make this hypothetical land one of our actual Zoological regions. It represents what was probably a primary Zoological region in some past geological epoch; but what that epoch was and what were the limits of the region in question, we are quite unable to say. If we are to suppose that it comprised the whole area now inhabited by Lemuroid animals, we must make it extend from West Africa to Burmah, South China, and Celebes; an area which it possibly did once occupy, but which cannot be formed into a modern Zoological region without violating much more important affinities. If, on the other hand, we leave out all those areas which undoubtedly belong to other regions, we reduce Lemuria to Madagascar and its adjacent {77}islands, which, for reasons already stated, it is not advisable to treat as a primary Zoological region. The theory of this ancient continent and the light it may throw on existing anomalies of distribution, will be more fully considered in the geographical part of this work.

_Australian Region._--Mr. Sclater's original name seems preferable to Professor Huxley's, "Austral-Asian;" the inconvenience of which alteration is sufficiently shown by the fact that Mr. Blyth proposed to use the very same term as an appropriate substitute for the "Indian region" of Mr. Sclater. Australia is the great central mass of the region; it is by far the richest in varied and highly remarkable forms of life; and it therefore seems in every way fitted to give a name to the region of which it is the essential element. The limits of this region in the Pacific are somewhat obscure, but as so many of the Pacific Islands are extremely poor zoologically, this is not of great importance.

_Sub-divisions of the Australian Region._--The first sub-region is the Austro-Malayan, including the islands from Celebes and Lombock on the west to the Solomon Islands on the east. The Australian sub-region comes next, consisting of Australia and Tasmania. The third, or Polynesian sub-region, will consist of all the tropical Pacific Islands, and is characterized by several peculiar genera of birds which are all allied to Australian types. The fourth, consists of New Zealand with Auckland, Chatham, and Norfolk Islands, and must be called the New Zealand sub-region.

The extreme peculiarities of New Zealand, due no doubt to its great isolation and to its being the remains of a more extensive land, have induced several naturalists to suggest that it ought justly to form a Zoological region by itself. But the inconveniences of such a procedure have been already pointed out; and when we look at its birds as a whole (they being the only class sufficiently well represented to found any conclusion upon) we find that the majority of them belong to Australian genera, and where the genera are peculiar they are most nearly related to Australian types. The preservation in these islands {78}of a single representative of a unique order of reptiles, is, as before remarked, of the same character as the preservation of the _Proteus_ in the caverns of Carniola; and can give the locality where it happens to have survived no claim to form a primary Zoological region, unless supported by a tolerably varied and distinctly characterized fauna, such as never exists in a very restricted and insular area.

_Neotropical Region._--Mr. Sclater's original name for this region is preserved, because change of nomenclature is always an evil; and neither Professor Huxley's suggested alteration "Austro-Columbia," nor Mr. Sclater's new term "Dendrogæa," appear to be improvements. The region is essentially a tropical one, and the extra-tropical portion of it is not important enough to make the name inappropriate. That proposed by Professor Huxley is not free from the same kind of criticism, since it would imply that the region was exclusively South American, whereas a considerable tract of North America belongs to it. This region includes South America, the Antilles and tropical North America; and it possesses more peculiar families of vertebrates and genera of birds and mammalia than any other region.

_Subdivisions of the Neotropical Region._--The great central mass of South America, from the shores of Venezuela to Paraguay and Eastern Peru, constitutes the chief division, and may be termed the Brazilian sub-region. It is on the whole a forest country; its most remarkable forms are highly developed arboreal types; and it exhibits all the characteristics of this rich and varied continent in their highest development.

The second, or Chilian sub-region, consists of the open plains, pampas, and mountains of the southern extremity of the continent; and we must include in it the west side of the Andes as far as the limits of the forest near Payta, and the whole of the high Andean plateaus as far as 4° of south latitude; which makes it coincide with the range of the Camelidæ and Chinchillidæ.

The third, or Mexican sub-region, consists of Central America and Southern Mexico, but it has no distinguishing {79}characteristics except the absence of some of the more highly specialized Neotropical groups. It is, however, a convenient division as comprising the portion of the North American continent which belongs zoologically to South America.

The fourth, or Antillean sub-region, consists of the West India islands (except Trinidad and Tobago, which are detached portions of the continent and must be grouped in the first sub-region); and these reproduce, in a much less marked degree, the phenomena presented by Madagascar. Terrestrial mammals are almost entirely wanting, but the larger islands possess three genera which are altogether peculiar to them. The birds are of South American forms, but comprise many peculiar genera. Terrestrial molluscs are more abundant and varied than in any part of the globe of equal extent; and if these alone were considered, the Antilles would constitute an important Zoological region.

_Nearctic Region._--This region comprises all temperate North America and Greenland. The arctic lands and islands beyond the limit of trees form a transitional territory to the Palæarctic region, but even here there are some characteristic species. The southern limit between this region and the Neotropical is a little uncertain; but it may be drawn at about the Rio Grande del Norte on the east coast, and a little north of Mazatlan on the west; while on the central plateau it descends much farther south, and should perhaps include all the open highlands of Mexico and Guatemala. This would coincide with the range of several characteristic Nearctic genera.

_Distinction of the Nearctic from the Palæarctic Region._--The Nearctic region possesses twelve peculiar families of vertebrates or one-tenth of its whole number. It has also twenty-four peculiar genera of mammalia and fifty-two of birds, in each case nearly one-third of all it possesses. This proportion is very nearly the same as in the Palæarctic region, while the number of peculiar families of vertebrata is very much greater. It has been already seen that both Mr. Blyth and Professor Huxley are disposed to unite this region with the Palæarctic, while Professor Newton, in his article on birds in the new edition of the {80}Encyclopædia Britannica, thinks that as regards that class it can hardly claim to be more than a sub-region of the Neotropical. These views are mutually destructive, but it will be shown in the proper place, that on independent grounds the Nearctic region can very properly be maintained.

_Subdivisions of the Nearctic Region._--The sub-regions here depend on the great physical features of the country, and have been in some cases accurately defined by American naturalists. First we have the Californian sub-region, consisting of California and Oregon--a narrow tract between the Sierra Nevada and the Pacific, but characterized by a number of peculiar species and by several genera found nowhere else in the region.

The second, or Rocky Mountain sub-region, consists of this great mountain range with its plateaus, and the central plains and prairies to about 100° west longitude, but including New Mexico and Texas in the South.

The third and most important sub-region, which may be termed the Alleghanian, extends eastward to the Atlantic, including the Mississippi Valley, the Alleghany Mountains, and the Eastern United States. This is an old forest district, and contains most of the characteristic animal types of the region.

The fourth, or Canadian sub-region, comprises all the northern part of the continent from the great lakes to the Arctic ocean; a land of pine-forests and barren wastes, characterized by Arctic types and the absence of many of the genera which distinguish the more southern portions of the region.

_Observations on the series of Sub-regions._--The twenty-four sub-regions here adopted were arrived at by a careful consideration of the distribution of the more important genera, and of the materials, both zoological and geographical, available for their determination; and it was not till they were almost finally decided on, that they were found to be equal in number throughout all the regions--four in each. As this uniformity is of great advantage in tabular and diagrammatic presentations of the distribution of the several families, I decided not to disturb it unless very strong reasons should appear for adopting a greater or less number in any particular case. Such however have not {81}arisen; and it is hoped that these divisions will prove as satisfactory and useful to naturalists in general as they have been to the author. Of course, in a detailed study of any region much more minute sub-division may be required; but even in that case it is believed that the sub-regions here adopted, will be found, with slight modifications, permanently available for exhibiting general results.

I give here a table showing the proportionate richness and speciality of each region as determined by its _families_ of vertebrates and _genera_ of mammalia and birds; and also a general table of the regions and sub-regions, arranged in the order that seems best to show their mutual relations.

COMPARATIVE RICHNESS OF THE SIX REGIONS.

+-------------+-----------------+
| | VERTEBRATA. |
| REGIONS. |Families|Peculiar|
| | |families|
+-------------+--------+--------+
| Palæarctic | 136 | 3 |
| Ethiopian | 174 | 22 |
| Oriental | 164 | 12 |
| Australian | 141 | 30 |
| Neotropical | 168 | 44 |
| Nearctic | 122 | 12 |
+-------------+--------+--------+

+-------------+-----------------------+-----------------------+
| | MAMMALIA. | BIRDS. |
| REGIONS. |Genera|Peculiar| Per |Genera|Peculiar| Per |
| | |genera |centage| |genera |centage|
+-------------+------+--------+-------+------+--------+-------+
| Palæarctic | 100 | 35 | 35 | 174 | 57 | 33 |
| Ethiopian | 140 | 90 | 64 | 294 | 179 | 60 |
| Oriental | 118 | 55 | 46 | 340 | 165 | 48 |
| Australian | 72 | 44 | 61 | 298 | 189 | 64 |
| Neotropical | 130 | 103 | 79 | 683 | 576 | 86 |
| Nearctic | 74 | 24 | 32 | 169 | 52 | 31 |
+-------------+------+--------+-------+------+--------+-------+

TABLE OF REGIONS AND SUB-REGIONS.

{83}CHAPTER V.

CLASSIFICATION AS AFFECTING THE STUDY OF GEOGRAPHICAL DISTRIBUTION.

A little consideration will convince us, that no inquiry into the causes and laws which determine the geographical distribution of animals or plants can lead to satisfactory results, unless we have a tolerably accurate knowledge of the affinities of the several species, genera, and families to each other; in other words, we require a natural classification to work upon. Let us, for example, take three animals--_a_, _b_, and _c_--which have a general external resemblance to each other, and are usually considered to be really allied; and let us suppose that _a_ and _b_ inhabit the same or adjacent districts, while c is found far away on the other side of the globe, with no animals at all resembling it in any of the intervening countries. We should here have a difficult problem to solve; for we should have to show that the general laws by which we account for the main features of distribution, will explain this exceptional case. But now, suppose some comparative anatomist takes these animals in hand, and finds that the resemblance of _c_ to _a_ and _b_ is only superficial, while their internal structure exhibits marked and important differences; and that _c_ really belongs to another group of animals, _d_, which inhabits the very region in which _c_ was found--and we should no longer have anything to explain. This is no imaginary case. Up to a very few years ago a curious Mexican animal, _Bassaris astuta_, was almost always classed in the civet family (Viverridæ), a group entirely {84}confined to Africa and Asia; but it has now been conclusively shown by Professor Flower that its real affinities are with the racoons (Procyonidæ), a group confined to North and South America. In another case, however, an equally careful examination shows, that an animal peculiar to the Himalayas (_Ælurus fulgens_) has its nearest ally in the _Cercoleptes_ of South America. Here, therefore, the geographical difficulty really exists, and any satisfactory theory of the causes that have led to the existing distribution of living things, must be able to account, more or less definitely, for this and other anomalies. From these cases it will be evident, that if any class or order of animals is very imperfectly known and its classification altogether artificial, it is useless to attempt to account for the anomalies its distribution may present; since those anomalies may be, to a great extent, due to false notions as to the affinities of its component species.

According to the laws and causes of distribution discussed in the preceding chapters, we should find limited and defined distribution to be the rule, universal or indefinite distribution to be the exception, in every natural group corresponding to what are usually regarded as families and genera; and so much is this the case in nature, that when we find a group of this nominal rank scattered as it were at random over the earth, we have a strong presumption that it is not natural; but is, to a considerable extent, a haphazard collection of species. Of course this reasoning will only apply, in cases where there are no unusual means of dispersal, nor any exceptional causes which might determine a scattered distribution.

From the considerations now adduced it becomes evident, that it is of the first importance for the success of our inquiry to secure a natural classification of animals, especially as regards the families and genera. The higher groups, such as classes and orders, are of less importance for our purpose; because they are almost always widely and often universally distributed, except those which are so small as to be evidently the nearly extinct representatives of a once more extensive series of forms. We now proceed to explain the classification to be adopted, as low down as the series of families. To these, equivalent English {85}names are given wherever they exist, in order that readers possessing no technical knowledge, may form some conception of the meaning of the term "family" in zoology.

The primary divisions of the animal kingdom according to two eminent modern authorities are as follows:

HUXLEY. CARUS AND GERSTAEKER.
Classification of Animals Handbuch der Zoologie
(1869). (1868).
1. Protozoa }
} 1. Protozoa.
2. Infusoria }
3. Coelenterata 2. Coelenterata.
4. Annuloida 3. Echinodermata.
{ 4. Vermes.
5. Annulosa {
{ 5. Arthropoda.
6. Molluscoida 6. Molluscoida.
7. Mollusca 7. Mollusca.
8. Vertebrata 8. Vertebrata.

For reasons already stated it is only with the fifth, seventh, and eighth of these groups that the present work proposes to deal; and even with the fifth and seventh only partially and in the most general way.

The classes of the vertebrata, according to both the authors above quoted, are: 1. Mammalia. 2. Aves. 3. Reptilia. 4. Amphibia. 5. Pisces, in which order they will be taken here.

The sub-classes and orders of mammalia are as follows:

MAMMALIA.

HUXLEY (1869), FLOWER (1870). CARUS (1868).
{ 1. Primates.
{ 1. Primates {
{ { 5. Prosimii.
{ 2. Chiroptera 2. Chiroptera.
{ 3. Insectivora 3. Insectivora.
{ { 6. Carnivora.
{ 4. Carnivora {
{ { 7. Pinnipedia.
Monodelphia { 5. Cetacea }
{ } 12. Natantia.
{ 6. Sirenia }
{ {10. Artiodactyla.
{ 7. Ungulata {
{ {11. Perissodactyla.
{ 8. Proboscidea 9. Proboscidea.
{ 9. Hyracoidea 8. Lamnungia.
{ 10. Rodentia 4. Rodentia.
{ 11. Edentata 13. Bruta.
{
Didelphia 12. Marsupialia 14. Marsupialia.
Ornithodelphia 13. Monotremata 15. Monotremata.

{86}The above series of orders is arranged according to Professor Flower's _Osteology of Mammalia_, and they will follow in this succession throughout my work. Professor Huxley arranges the same orders in a different series.

In determining the manner in which the several orders shall be subdivided into families, I have been guided in my choice of classifications mainly by the degree of attention the author appears to have paid to the group, and his known ability as a systematic zoologist; and in a less degree by considerations of convenience as regards the special purposes of geographical distribution. In many cases it is a matter of great doubt whether a certain group should form several distinct families or be united into one or two; but one method may bring out the peculiarities of distribution much better than the other, and this is, in our case, a sufficient reason for adopting it.

For the Primates I follow, with some modifications, the classification of Mr. St. George Mivart given in his article "Apes" in the new edition of the _Encyclopædia Britannica_, and in his paper in the _Proceedings of the Zoological Society of London_, 1865, p. 547. It is as follows:

Order--PRIMATES, divided into two Sub-orders:
I. Anthropoidea.
II. Lemuroidea.

Sub-order--ANTHROPOIDEA.
Fam.
Hominidæ Man.

{ 1. Simiidæ Anthropoid Apes.
Simii { 2. Semnopithecidæ Old-world Monkeys.
{ 3. Cynopithecidæ Baboons and Macaques.

Cebii { 4. Cebidæ American Monkeys.
{ 5. Hapalidæ Marmosets.

Sub-order--LEMUROIDEA.

Fam.
6. Lemuridæ Lemurs.
7. Tarsiidæ Tarsiers.
8. Chiromyidæ Aye-ayes.

Omitting man (for reasons stated in the preface) the three first families are considered by Professor Mivart to be sub-families of Simiidæ; but as the geographical distribution of the Old World apes is especially interesting, it is thought {87}better to treat them as families, a rank which is claimed for the anthropoid apes by many naturalists.

As no good systematic work on the genera and species of bats has been yet published, I adopt the five families as generally used in this country, with the genera as given in the papers of Dr. J. E. Gray and Mr. Tomes. A monograph by Dr. Peters has long been promised, and his outline arrangement was published in 1865, but this will perhaps be materially altered when the work appears.

Order--CHIROPTERA.

Fam.

Frugivora 9. Pteropidæ Fruit-eating Bats.

{Istiophora { 10. Phyllostomidæ Leaf-nosed Bats.
Insectivora { { 11. Rhinolophidæ Horse-shoe Bats.
{
{Gymnorhini { 12. Vespertilionidæ True Bats.
{ 13. Noctilionidæ Dog-headed Bats.

The genera of Chiroptera are in a state of great confusion, the names used by different authors being often not at all comparable, so that the few details given of the distribution of the bats are not trustworthy. We have therefore made little use of this order in the theoretical part of the work.

The osteology of the Insectivora has been very carefully worked out by Professor Mivart in the _Jounral of Anatomy and Physiology_ (Vol. ii., p. 380), and I follow his classification as given there, and in the _Proceedings of the Zoological Society_ (1871).

Order--INSECTIVORA.

Fam.
14. Galeopithecidæ Flying Lemurs.
15. Macroscelididæ Elephant Shrews.
16. Tupaiidæ Squirrel Shrews.
17. Erinaceidæ Hedgehogs.
18. Centetidæ Tenrecs.
19. Potamogalidæ Otter Shrew.
20. Chrysochloridæ Golden Moles.
21. Talpidæ Moles.
22. Soricidæ Shrews.

The next order, Carnivora, has been studied in detail by Professor Flower; and I adopt the classification given by him in the _Proceedings of the Zoological Society_, 1869, p. 4.

{88}Order--CARNIVORA.

Fam.
{ 23. Felidæ Cats, Lion, &c.
{ 24. Cryptoproctidæ Cryptoprocta.
{ Æluroidea { 25. Viverridæ Civets.
{ { 26. Protelidæ Aard-wolf.
{ { 27. Hyænidæ Hyænas.
{
Fissipedia { Cynoidea 28. Canidæ Dogs, Foxes, &c.
{
{ {29. Mustelidæ Weasels.
{ {30. Procyonidæ Racoons.
{ Arctoidea {31. Æluridæ Pandas.
{32. Ursidæ Bears.

{33. Otariidæ Eared Seals.
Pinnipedia {34. Trichechidæ Walrus.
{35. Phocidæ Seals.

The Cetacea is one of those orders the classification of which is very unsettled. The animals comprising it are so huge, and there is so much difficulty in preserving them, that only a very few species are known with anything like completeness. A considerable number of genera and species have been described or indicated; but as many of these are founded on imperfect specimens of perhaps a single individual, it is not to be wondered at that those few naturalists who occupy themselves with the study of these large animals, cannot agree as to the proper mode of grouping them into natural families. They are, however, of but little importance to us, as almost all the species inhabit the ocean, and of only a few of them can it be said that anything is accurately known of their distribution. I therefore consider it best to follow Professor Carus, who makes a smaller number of families; but I give also the arrangement of Dr. Gray in his British Museum catalogue of whales and seals, as modified subsequently in the _Proceedings of Zoological Society_, 1870, p. 772. The Zeuglodontidæ, a family of extinct tertiary whales, are classed by Professors Owen and Carus between Cetacea and Sirenia, while Professor Huxley considers them to have been carnivorous and allied to the seals.

{89}Order--CETACEA.

Fam. (CARUS). Fam. (GRAY).

Sub-order I.-- { Balænidæ 36. Balænidæ.
Mystaceti. { Balænopteridæ 37. Balænopteridæ.

{ Catodontidæ 38. Catodontidæ.
{
{ { Hyperoodontidæ.
{ Hyperoodontidæ 39. { Epiodontidæ.
{ { Xiphiadæ.
{
Sub-order II.-- { Monodontidæ 40. (Part of Delphinidæ.)
Odontoceti {
{ { Platanistidæ.
{ { Iniadæ.
{ { Delphinidæ.
{ Delphinidæ 41. { Globiocephalidæ.
{ Orcadæ.
{ Belugidæ.
{ Pontoporiadæ.

Extinct family Zeuglodontidæ.

Order--SIRENIA.

The order Sirenia, comprising the sea-cows, consists of a single family:

Family 42. Manatidæ.

The extensive order Ungulata comprises the three orders Pachydermata, Solidungula, and Ruminantia of the older naturalists. The following classification is that now generally adopted, the only difference of opinion being as to whether some of the groups should be classed as families or sub-families, a matter of little importance for our purpose:

Order--UNGULATA.

Fam.

Perissodactyla or } 43. Equidæ Horses.
Odd-toed Ungulates } 44. Tapiridæ Tapirs.
45. Rhinocerotidæ Rhinoceros.

{ Suina { 46. Hippopotamidæ Hippopotamus.
{ { 47. Suidæ Swine.
{
Artiodactyla or { Tylopoda 48. Camelidæ Camels.
Even-toed Ungulates {
{ Tragulina 49. Tragulidæ Chevrotains.
{
{ { 50. Cervidæ Deer.
{ Pecora { 51. Camelopardidæ Giraffes.
{ 52. Bovidæ { Cattle, Sheep,
{ Antelopes, &c.

{90}The two next orders consist of but a single family each, viz.:

Order Fam.

PROBOSCIDEA 53. Elephantidæ Elephants.
HYRACOIDEA 54. Hyracidæ Rock-rabbits.

We now come to the Rodentia, a very extensive and difficult order, in which there is still much difference of opinion as to the details of classification, although the main outlines are pretty well settled. The foundations of a true classification of this order were laid by Mr. G. R. Waterhouse more than thirty years ago, and succeeding authors have done little more than follow his arrangement with unimportant modifications. Professor Lilljeborg, of Upsala, has however made a special study of this group of animals, and has given an original and detailed classification of all the genera. (_Systematisk Öfversigt af de Gnagande Däggdjuren, Glires. Upsala, 1866._) I follow this arrangement with a few slight modifications suggested by other naturalists, and which make it better adapted for the purposes of this work.

Order--RODENTIA.

Fam.

{ 55. Muridæ Rats.
{ 56. Spalacidæ Mole-rats.
{ 57. Dipodidæ Jerboas.
{ 58. Myoxidæ Dormice.
{ Murina { 59. Saccomyidæ Pouched Rats.
{ (Waterhouse) { 60. Castoridæ Beavers.
{ { 61. Sciuridæ Squirrels.
Simplicidentati { { 62. Haploodontidæ Sewellels.
{
{ { 63. Chinchillidæ Chinchillas.
{ { 64. Octodontidæ Octodons.
{ Hystricina { 65. Echimyidæ Spiny Rats.
(Waterhouse) { 66. Cercolabidæ Tree Porcupines
{ 67. Hystricidæ Porcupines.
{ 68. Caviidæ Cavies.

Duplicidentati { Leporina { 69. Lagomyidæ Pikas.
{ (Waterhouse) { 70. Leporidæ Hares.

The Edentata have been classified by Mr. Turner, in the _Proceedings of the Zoological Society_ (1851, p. 205), by Dr. Gray in the British Museum Catalogue, and by Professor Carus in his _Handbuch_. The former takes a middle course between {91}the numerous families of Dr. Gray, seven in number, and the two families to which Professor Carus restricts the existing species. I therefore follow Mr. Turner.

Order--EDENTATA.

Fam.

Bradypoda 71. Bradypodidæ Sloths.
{ 72. Manididæ Scaly Ant-eaters.
{ 73. Dasypodidæ Armadillos.
Entomophaga { 74. Orycteropodidæ Ant-bears.
{ 75. Myrmecophagidæ Ant-eaters.

The Marsupials have been well classified and described by Mr. Waterhouse in the first volume of his _Natural History of Mammalia_, and his arrangement is here followed. The suborders adopted by Professor Carus are also given.

Order--MARSUPIALIA.

Fam.

{ 76. Didelphidæ Opossums.
{ 77. Dasyuridæ Native Cats.
Rapacia (Wagner) { 78. Myrmecobiidæ Native Ant-eater.
{ 79. Peramelidæ Bandicoots.
Poephaga (Owen) 80. Macropodidæ Kangaroos.
Carpophaga (Owen) 81. Phalangistidæ Phalangers.
Rhizophaga (Owen) 82. Phascolomyidæ Wombats.

Order--MONOTREMATA.

The last order, the Monotremata, consist of two families, which Professor Carus combines into one, but which it seems more natural to keep separate.

Fam.

83. Ornithorhynchidæ Duckbill.
84. Echidnidæ Echidna.

{92}BIRDS.

Birds are perhaps the most difficult to classify of all the divisions of the vertebrata. The species and genera are exceedingly numerous, and there is such a great uniformity in general structure and even in the details of external form, that it is exceedingly difficult to find characters by which orders and families can be characterised. For a long time the system of Vigors and Swainson was followed; but this wholly ignored anatomical characters and in many cases plainly violated well-marked affinities. Characters derived from the form of the sternum, the scutellation of the tarsi, and the arrangement of the feathers, have all assisted in determining natural groups. More recently Professor Huxley has applied the variations of the bony palate to the general arrangement of birds; and still more recently Professor Garrod has studied certain leg-muscles for the same purpose. The condition of the young as regards plumage, and even the form, texture, and coloration of the egg, have also been applied to solve doubtful cases of affinity; yet the problem is not settled, and it will probably remain for another generation of ornithologists to determine with any approach to accuracy what are the most natural divisions of the class into orders and families. In a work like the present it is evidently not advisable to adopt all the recent classifications; since experience has shown that no arrangement in which one set of characters is mainly relied on, long holds its ground. Such modifications of the old system as seem to be well established will be adopted; but the older groups will be adhered to in cases where the most recent classifications are open to doubt, or seem inconvenient as separating families, which, owing to their similarity in general structure, form and habits are best kept together for the purposes of geographical distribution.

The old plan of putting the birds of prey at the head of the class, is now almost wholly given up; both because they are not {93}the most highly organised, but only one of the most specialised forms of birds, and because their affinities are not with the Passeres, but rather with the cormorants and some other of the aquatic groups. The Passeres therefore are placed first; and the series of families is begun by the thrushes, which are certainly the most typical and generally well-organised form of birds. Instead of the Scansores and Fissirostres of the older authors, the order Picariæ, which includes them both, is adopted, but with some reluctance; as the former are, generally speaking, well marked and strongly contrasted groups, although certain families have been shown to be intermediate. In the Picariæ are included the goat-suckers, swifts, and humming-birds, sometimes separated as a distinct order, Macrochires. The parrots and the pigeons form each a separate order. The old groups of Grallæ and Anseres are preserved, as more convenient than breaking them up into widely separated parts; for though the latter plan may in some cases more strictly represent their affinities, its details are not yet established, nor is it much used by ornithologists. In accordance with these views the following is the series of orders and families of birds adopted in this work:

Class--AVES.

Orders.

1. Passeres { Including the great mass of the smaller birds--Crows,
{ Finches, Flycatchers, Creepers, Honeysuckers, &c., &c.

2. Picariæ { Including Woodpeckers, Cuckoos, Toucans, Kingfishers,
{ Swifts, &c., &c.

3. Psittaci Parrots only.
4. Columbæ Pigeons and the Dodo.
5. Gallinæ Grouse, Pheasants, Curassows, Mound-builders, &c.
6. Opisthocomi The Hoazin only.
7. Accipitres Eagles, Owls, and Vultures.
8. Grallæ Herons, Plovers, Rails, &c.
9. Anseres Gulls, Ducks, Divers, &c.
10. Struthiones Ostrich, Cassowary, Apteryx, &c.

The Passeres consist of fifty families, which may be arranged and grouped in series as follows. It must however be remembered that the first family in each series is not always that which is most allied to the last family of the preceding series. All extensive natural groups consist of divergent or branching alliances, which renders it impossible to arrange the whole in one continuous series.

{94}A.--TYPICAL OR TURDOID PASSERES.

1. Turdidæ Thrushes.
2. Sylviidæ Warblers.
3. Timaliidæ Babblers.
4. Panuridæ Reedlings.
5. Cinclidæ Dippers.
6. Troglodytidæ Wrens.
7. Chamæidæ
8. Certhiidæ Creepers.
9. Sittidæ Nuthatches.
10. Paridæ Tits.
11. Liotrichidæ Hill-tits.
12. Phyllornithidæ Green Bulbuls.
13. Pycnonotidæ Bulbuls.
14. Oriolidæ Orioles.
15. Campephagidæ Caterpillar-shrikes.
16. Dicruridæ Drougos.
17. Muscicapidæ Flycatchers.
18. Pachycephalidæ Thick-heads.
19. Laniidæ Shrikes.
20. Corvidæ Crows.
21. Paradiseidæ Paradise-birds.
22. Meliphagidæ Honey-suckers.
23. Nectarineidæ Sun-birds.

B.--TANAGROID PASSERES.

24. Dicæidæ Flower-peckers.
25. Drepanididæ
26. Cærebidæ Sugar-birds.
27. Mniotiltidæ Wood-warblers.
28. Vireonidæ Greenlets.
29. Ampelidæ Waxwings.
30. Hirundinidæ Swallows.
31. Icteridæ Hangnests.
32. Tanagridæ Tanagers.
33. Fringillidæ Finches.

C.--STURNOID PASSERES.

34. Ploceidæ Weaver-birds.
35. Sturnidæ Starlings.
36. Artamidæ Swallow-shrikes.
37. Alaudidæ Larks.
38. Motacillidæ Wagtails.

D.--FORMICAROID PASSERES.

39. Tyrannidæ Tyrants.
40. Pipridæ Manakins.
41. Cotingidæ Chatterers.
42. Phytotomidæ Plant-cutters.
43. Eurylæmidæ Broad-bills.
44. Dendrocolaptidæ American Creepers.
45. Formicariidæ Ant-thrushes.
46. Pteroptochidæ {95}
47. Pittidæ Pittas.
48. Paictidæ

E.--ANOMALOUS PASSERES.

49. Menuridæ Lyre-birds.
50. Atrichidæ Scrub-birds.

The preceding arrangement is a modification of that proposed by myself in the _Ibis_ (1874, p. 406). The principal alterations are adding the families Panuridæ and Sittidæ in series A, commencing series B with Dicæidæ; bringing Vireonidæ next to the allied American family Mniotiltidæ; and placing Motacillidæ in series C next to Alaudidæ. At the suggestion of Professor Newton I place Menuridæ and Atrichidæ apart from the other Passeres, as they both possess striking peculiarities of anatomical structure.

The heterogeneous families constituting the order Picariæ may be conveniently arranged as follows:

{ 51. Picidæ Woodpeckers.
{ 52. Yungidæ Wrynecks.
{ 53. Indicatoridæ Honey-guides.
Sub-order-- { 54. Megalæmidæ Barbets.
Scansores. { 55. Rhamphastidæ Toucans.
{ 56. Musophagidæ Plantain-eaters.
{ 57. Coliidæ Colies.
{ 58. Cuculidæ Cuckoos.

Intermediate 59. Leptosomidæ The Leptosoma.

{ 60. Bucconidæ Puff-birds.
{ 61. Galbulidæ Jacamars.
{ 62. Coraciidæ Rollers.
{ 63. Meropidæ Bee-eaters.
{ 64. Todidæ Todies.
{ 65. Momotidæ Motmots.
{ 66. Trogonidæ Trogons.
Sub-order-- { 67. Alcedinidæ Kingfishers.
Fissirostres. { 68. Bucerotidæ Hornbills.
{ 69. Upupidæ Hoopoes.
{ 70. Irrisoridæ Promerops.
{ 71. Podargidæ Frog-mouths.
{ 72. Steatornithidæ The Guacharo.
{ 73. Caprimulgidæ Goatsuckers.
{ 74. Cypselidæ Swifts.
{ 75. Trochilidæ Humming-birds.

{96}The Psittaci or parrot tribe are still in a very unsettled state of classification; that recently proposed by Professor Garrod differing widely from the arrangement adopted in Dr. Finsch's monograph of the order. Taking advantage of the researches of these and other authors, the following families are adopted as the most convenient in the present state of our knowledge:

76. Cacatuidæ The Cockatoos.
77. Platycercidæ The Broad-tailed Paroquets of Australia.
78. Palæornithidæ The Oriental Parrots and Paroquets.
79. Trichoglossidæ The Brush-tongued Paroquets and Lories.
80. Conuridæ The Macaws and their allies.
81. Psittacidæ The African and South American Parrots.
82. Nestoridæ The Nestors of New Zealand.
83. Stringopidæ The Owl-parrots of New Zealand.

The Columbæ, or pigeons, are also in a very unsatisfactory state as regards a natural classification. The families, sub-families, and genera proposed by various authors are very numerous, and often quite irreconcilable. I therefore adopt only two families; and generally follow Mr. G. R. Gray's hand-list for the genera, except where trustworthy authorities exist for a different arrangement. The families are:

84. Columbidæ Pigeons and Doves.
85. Dididæ The extinct Dodo and allies.

The Gallinæ, or game-birds, may be divided into seven families:

Fam. Sub-fam.

86. Pteroclidæ Sand-grouse.
87. Tetraonidæ Partridges and Grouse.
{ Pavoninæ Peafowl.
{ Lophophorinæ Tragopans, &c.
{ Phasianinæ Pheasants.
88. Phasianidæ { Euplocaminæ Fire-backed Pheasants, &c.
{ Gallinæ Jungle-fowl.
{ Meleagrinæ Turkeys.
{ Numidinæ Guinea-fowl.
89. Turnicidæ Hemipodes.
90. Megapodiidæ Mound-makers.
{ Cracinæ Curassows.
91. Cracidæ { Penelopinæ Guans.
{ Oreophasinæ Mountain-pheasant.
92. Tinamidæ Tinamous.

{97}The Opisthocomi consist of one family containing a single species, the "Hoatzin" of Guiana.

Family 93. Opisthocomidæ.

The Accipitres, or birds of prey, which were long considered to be the highest and most perfect order of birds, are now properly placed lower down in the series, their affinities being more with the aquatic than with the perching birds. The following is the arrangement adopted by Mr. Sharpe in his recently published British Museum catalogue of diurnal birds of prey:--

Sub-orders. Fam. Sub-families.

{ Vulturinæ Vultures.
{ 94. Vulturidæ { Sarcorhamphinæ Turkey-buzzards.
{
Falcones { 95. Serpentariidæ
{
{ { Polyborniæ Caracaras.
{ { Accipitrinæ Hawks.
{ 96. Falconidæ { Buteoninæ Buzzards.
{ Aquilinæ Eagles.
{ Falconinæ Falcons.

Pandiones 97. Pandionidæ Fishing-eagles.
Striges 98. Strigidæ Owls.

The Grallæ or Grallatores are in a very unsettled state. The following series of families is in accordance with the views of some of the best modern ornithologists:

99. Rallidæ Rails, &c.
100. Scolopacidæ Sandpipers and Snipes
101. Chionididæ Sheath-bills.
102. Thinocoridæ Quail-snipes.
103. Parridæ Jacanas.
104. Glareolidæ Pratincoles.
105. Charadriidæ Plovers.
106. Otididæ Bustards.
107. Gruidæ Cranes.
108. Cariamidæ Cariamas.
109. Aramidæ Guaraunas.
110. Psophiidæ Trumpeters.
111. Eurypygidæ Sun-bitterns.
112. Rhinochoetidæ Kagus.
113. Ardeidæ Herons.
114. Plataleidæ Spoonbills and Ibis.
115. Ciconiidæ Storks.
116. Palamedeidæ Screamers.
117. Phænicopteridæ Flamingoes.

{98}The Anseres or Natatores are almost equally unsettled. The flamingoes are usually placed in this order, but their habits best assort with those of the waders.

Fam.

118. Anatidæ Duck and Geese.
119. Laridæ Gulls.
120. Procellariidæ Petrels.
121. Pelecanidæ Pelicans.
122. Spheniscidæ Penguins.
123. Colymbidæ Divers.
124. Podicipidæ Grebes.
125. Alcidæ Auks.

The last order of birds is the Struthiones or Ratitæ, considered by many naturalists to form a distinct sub-class. It consists of comparatively few species, either living or recently extinct.

Fam.

{ 126. Struthionidæ Ostriches.
Living { 127. Casuariidæ Cassowaries.
{ 128. Apterygidæ Apteryx.

{ 129. Dinornithidæ Dinornis.
Extinct { 130. Palapterygidæ Palapteryx.
{ 131. Æpyornithidæ Æpyornis.

REPTILES.

In reptiles I follow the classification of Dr. Günther as given in the _Philosophical Transactions_, vol. clvii., p. 625. He divides the class into five orders as follows:--

Sub-classes. Orders.

{ 1. Ophidia Serpents.
I. Squamata { 2. Lacertilia Lizards.
{ 3. Rhyncocephalina The Hatteria.

II. Loricata 4. Crocodilia Crocodiles.

III. Cataphracta 5. Chelonia Tortoises.

In the arrangement of the families comprised in each of these orders I also follow the arrangement of Dr. Günther and Dr. J. E. Gray, as given in the British Museum Catalogue, or as modified by the former gentleman who has kindly given me much personal information.

{99}The Ophidia, or Snakes, form the first order and are classified as follows:--

Fam.

{ 1. Typhlopidæ }
{ 2. Tortricidæ }
{ 3. Xenopeltidæ } Burrowing Snakes.
{ 4. Uropeltidæ }
{ 5. Calamaridæ Dwarf ground-snakes.
{ 6. Oligodontidæ.
{ 7. Colubridæ Colubrine Snakes.
{ 8. Homalopsidæ Fresh-water Snakes.
{ 9. Psammophidæ Desert-snakes.
Innocuous Snakes { 10. Rachiodontidæ.
{ 11. Dendrophidæ Tree-snakes.
{ 12. Dryiophidæ Whip-snakes.
{ 13. Dipsasidæ Nocturnal tree-snakes.
{ 14. Scytalidæ
{ 15. Lycodontidæ Fanged ground-snakes.
{ 16. Amblycephalidæ Blunt-heads.
{ 17. Pythonidæ Pythons.
{ 18. Erycidæ Sand-snakes.
{ 19. Acrochordidæ Wart-snakes.

{ 20. Elapidæ Cobras, &c.
Venomous Colubrine { 21. Dendraspididæ.
Snakes { 22. Atractaspididæ.
{ 23. Hydrophidæ Sea-snakes.

{ 24. Crotalidæ Pit-vipers.
Viperine Snakes { 25. Viperidæ True vipers.

The second order, Lacertilia, are arranged as follows:--

Fam.

26. Trogonophidæ }
27. Chirotidæ }
28. Amphisbænidæ } Amphisbænians.
29. Lepidosternidæ }
30. Varanidæ Water Lizards.
31. Helodermidæ.
32. Teidæ Teguexins.
33. Lacertidæ } Land Lizards.
34. Zonuridæ }
35. Chalcidæ.
36. Anadiadæ.
37. Chirocolidæ.
38. Iphisadæ.
39. Cercosauridæ.
40. Chamæsauridæ.
41. Gymnopthalmidæ Gape-eyed Scinks.
42. Pygopodidæ Two-legged Lizards.
43. Aprasiadæ.
44. Lialidæ. {100}
45. Scincidæ Scinks.
46. Ophiomoridæ Snake-lizards.
47. Sepidæ Sand-lizards.
48. Acontiadæ.
49. Geckotidæ Geckoes.
50. Iguanidæ Iguanas.
51. Agamidæ Fringed Lizards.
52. Chameleonidæ Chameleons.

The third order, Rhyncocephalina consists of a single family:--

53. Rhyncocephalidæ The Hatteria of New Zealand.

The fourth order, Crocodilia or Loricata, consists of three families:--

54. Gavialidæ Gavials.
55. Crocodilidæ Crocodiles.
56. Alligatoridæ Alligators.

The fifth order, Chelonia, consists of four families:--

57. Testudinidæ Land and fresh-water Tortoises.
58. Chelydidæ Fresh-water Turtles.
59. Trionychidæ Soft Turtles.
60. Cheloniidæ Sea Turtles.

AMPHIBIA.

In the Amphibia I follow the classification of Professor Mivart, as given for a large part of the order in the _Proceedings of the Zoological Society_ for 1869. For the remainder I follow Dr. Strauch, Dr. Günther, and a MSS. arrangement kindly furnished me by Professor Mivart.

The class is first divided into three groups or orders, and then into families as follows:--

{101}Order I.--PSEUDOPHIDIA.

Fam.

1. Cæciliadæ Cæcilia.

Order II.--BATRACHIA URODELA.

2. Sirenidæ Siren.
3. Proteidæ Proteus.
4. Amphiumidæ Amphiuma.
5. Menopomidæ Giant Salamanders.
6. Salamandridæ Salamanders and Newts.

Order III.--BATRACHIA ANOURA.

7. Rhinophrynidæ }
8. Phryniscidæ }
9. Hylaplesidæ } Toads.
10. Bufonidæ }
11. Xenorhinidæ }
12. Engystomidæ }

13. Bombinatoridæ }
14. Plectromantidæ } Frogs.
15. Alytidæ }

16. Pelodryadæ }
17. Hylidæ } Tree Frogs.
18. Polypedatidæ }

19. Ranidæ } Frogs.
20. Discoglossidæ }

21. Pipidæ } Tongueless
22. Dactylethridæ } Toads.

FISHES.

These are arranged according to the classification of Dr. Günther, whose great work "The British Museum Catalogue of Fishes," has furnished almost all the material for our account of the distribution of the class.

In that work all existing fishes are arranged in six sub-classes and thirteen orders. A study of the extraordinary _Ceratodus_ from Australia has induced Dr. Günther to unite three of his sub-classes; but as his catalogue will long remain a handbook for every student of fishes, it seems better to follow the arrangement there given, indicating his later views by bracketing together the groups he now thinks should be united.

-----------------------------------------+---------+--------------- {102}
Sub-class. Order. |Families.| Remarks.
-----------------------------------------+---------+------------------
{ 1. Acanthopterygii | 47 | Gasterosteidæ to
{ | | Notacanthi.
{ 2. Do. Pharyncognathi | 5 | Pomacentridæ to
{ | | Chromidæ.
Ganoidei { 3. Acanthini | 6 | Gadopsidæ to
======== { | | Pleuronectidæ.
{Teleostei { 4. Physostomi | 29 | Siluridæ to
{ { | | Pegasidæ.
{ { 5. Lophobranchii | 2 | Solenostomidæ and
{ { | | Syngnathidæ.
{ { 6. Plectognathi | 2 | Sclerodermi and
{ { | | Gymnodontes.
{ | |
{Dipnoi 7. Sirenoidei | 1 | Sirenoidei.
{ | |
{ { 8. Holostei | 3 | Amiidæ to
{ { | | Lepidosteidæ.
{Ganoidei { 9. Chondrostei | 2 | Accipenseridæ and
{ | | Polydontidæ.
| |
Chondropterygii { 10. Holocephala | 1 | Chimæridæ.
{ 11. Plagiostomata | 15 | Carchariidæ to
| | Myliobatidæ.
| |
Cyclostomata 12. Marsipobranchii | 2 | Petromyzontidæ and
| | Myxinidæ.
| |
Leptocardii 13. Cirrhostomi | 1 | Cirrhostomi.
+---------+
Total 116 families.
-----------------------------------------------------------------------

INSECTS.

The families and genera of insects are so immensely numerous, probably exceeding fifty-fold those of all other land animals, that for this cause alone it would be impossible to enter fully into their distribution. It is also quite unnecessary, because many of the groups are so liable to be transported by accidental causes, that they afford no useful information for our subject; while others are so obscure and uninteresting that they have been very partially collected and studied, and are for this reason equally ineligible. I have therefore selected a few of the largest and most conspicuous families, which have been so assiduously collected in every part of the globe, and so carefully studied at home, as to afford valuable materials for comparison with the vertebrate groups, when we have made due allowance for the dependence of many insects on peculiar forms of vegetation, and the facility with which many of them are transported either in the egg, larva, or perfect state, by winds, currents, and other less known means.

I confine myself then, almost exclusively, to the sixteen families of Diurnal Lepidoptera or butterflies, and to six of the most extensive, conspicuous, and popular families of Coleoptera. {103}The number of species of Butterflies is about the same as that of Birds, while the six families of Coleoptera selected, comprise more than twenty thousand species, far exceeding the number of all other vertebrates. These families have all been recently catalogued, so that we have very complete information as to their arrangement and distribution.

LEPIDOPTERA DIURNA, OR BUTTERFLIES.

Fam.

1. Danaidæ.
2. Satyridæ.
3. Elymniidæ.
4. Morphidæ.
5. Brassolidæ.
6. Acræidæ.
7. Heliconidæ.
8. Nymphalidæ.
9. Libythæidæ.
10. Nemeobiidæ.
11. Eurygonidæ.
12. Erycinidæ.
13. Lycænidæ.
14. Pieridæ.
15. Papilionidæ.
16. Hesperidæ.

COLEOPTERA, OR BEETLES.

Fam.

1. Cicindelidæ Tiger-beetles.
2. Carabidæ Ground-beetles.
3. Lucanidæ Stag-beetles.
4. Cetoniidæ Rose-chafers.
5. Buprestidæ Metallic Beetles.
6. Longicornia Long-horned Beetles.

The above families comprise the extensive series of ground beetles (Carabidæ) containing about 9,000 species, and the Longicorns, which are nearly as numerous and surpass them in variety of form and colour as well as in beauty. The Cetoniidæ and Buprestidæ are among the largest and most brilliant of beetles; the Lucanidæ are pre-eminent for remarkable form, and the Cicindelidæ for elegance; and all the families are especial favourites with entomologists, so that the whole earth has been ransacked to procure fresh species.

Results deduced from a study of these will, therefore, fairly represent the phenomena of distribution of Coleoptera, and, as they are very varied in their habits, perhaps of insects in general.

{104}MOLLUSCA.

The Mollusca are usually divided into five classes as follows:--

Classes.

I. Cephalopoda Cuttle-fish.
II. Gasteropoda Snails and aquatic Univalves.
III. Pteropoda Oceanic Snails.
IV. Brachiopoda Symmetrical Bivalves.
V. Conchifera Unsymmetrical Bivalves.

The Gasteropoda and Conchifera alone contain land and freshwater forms, and to these we shall chiefly confine our illustrations of the geographical distribution of the Mollusca. The classification followed is that of Dr. Pfeiffer for the Operculata and Dr. Von Martens for the Helicidæ. The families chiefly referred to are:--

Class II.--GASTEROPODA.

Order 2.--Pulmonifera.

Fam.

{ 1. Helicidæ.
{ 2. Limacidæ.
{ 3. Oncidiadæ.
In-operculata { 4. Limnæidæ.
{ 5. Auriculidæ.
{ 6. Aciculidæ.
{ 7. Diplommatinidæ.

Operculata { 8. Cyclostomidæ.
{ 9. Helicinidæ.

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