of toads. There are also three peculiar families of freshwater fishes.

It is impossible to give any idea of the special features presented by the insects and land-shells without going into details which would be out of place in such a sketch as we are here giving. In both these groups Africa is fully as rich as the other tropical regions, and exhibits perhaps more peculiar features than among the higher animals.

We must, however, just mention the remarkable absence from the Ethiopian region of certain groups of Mammalia which abound in the countries to the north and east of it, as this phenomenon has an important bearing on the probable origin of the fauna. The most striking of these deficiencies are the two families of the deer and the bears, which abound over the whole northern hemisphere, in tropical Asia and the Malay islands, and even in North Africa, but are both entirely unknown over the whole Ethiopian region, as are, among smaller groups, the goats and sheep, the true oxen, and the mole family. Among birds such wide-sprzad groups as the wrens (Troglodytidae), dippers (Cinclidae), and the true pheasants are also entirely wanting.

The exceeding speciality of the forms of life which are still found in the Ethiopian region is well shown by the fact that there are about 24 family groups of vertebrate animals which are entirely confined to it, while two-thirds of its genera of Mammalia, and three-fifths of the genera of birds, are also peculiar.

Subdivisions of the Ethiopian Region.-The most remarkable of these is undoubtedly that comprising Madagascar and the Mascarene islands, a district which contains so many singular forms of life that it has been proposed by some naturalists to make it one of the primary zoological regions. The peculiarity of these islands is twofold, consisting as much in the absence of a great number of the most characteristic African forms as in the possession of others entirely peculiar. The apes and monkeys, the large Carnivora, the zebras, giraffes, antelopes, elephants, and rhinoceroses, and even such smaller forins as the porcupines and squirrels, are entirely wanting. Yet Madagascar possesses a host of remarkable Lemur ida, consisting of 7 genera and 35 species, all of which are peculiar; a peculiar family of Insectivora, comprising 5 genera and 10 species; a peculiar family and 5 peculiar genera of small Carnivora; and 3 peculiar genera of Merida. Even among birds, so much better able to traverse a narrow sea, there are some curious deficiencies, the families of woodpeckers (Picida), honey-guides (Indicatorida), barbets (Megalamida), plantain - eaters (Musophagida), colies (Coliida), hornbills (Bucerotidae), and mockers (Irrisorida)-all abundant on the opposite coast of Africa-being entirely wanting. Yet birds are sufficiently abundant, nearly 120 species of true landbirds being known, while there are no less than 33 genera which are altogether confined to Madagascar and the Mascarene islands. If we consider the species, the peculiarity is even more remarkable, there being more than a hundred which are peculiar to about a dozen which are found elsewhere. These numbers, however, by no means fairly represent the special character of the Mascarene birdfauna, which consists in the anomalous character of many of the genera, so that it is to this day a matter of dispute among ornithologists in what families a considerable number of them should be classed. Among these anomalous genera are Mesites, Tylas, Artamia, Calicalicus, Euryceros, Philepitta, Leptosomus, Atelornis, and several others. Taking all these facts into consideration, we arrive at the conclusion that the fauna of Madagascar is more peculiar than that of any other single island on the globe.

The reptiles of Madagascar are less known, but they exhibit some remarkable peculiarities. Many African groups are wanting, others are represented by peculiar genera, while a considerable number of groups have their nearest allies, not in Africa, but in tropical Asia and in South America. Among insects the butterflies are allied to those of Africa; but the beetles, like the reptiles, show many cases

of allinity with the Malay islands and South America, though the majority are perhaps related to true Ethiopian forms.

The continental part of the Ethiopian region appears to have no subdivisions clearly marked out by natural barriers, yet it may be divided into three tolerably well-defined sub-regions in accordance with differences of climate and vegetation. These may be termed the sub-region of open plains, the forest sub-region, and the south temperate sub-region.

The first comprises the greater part of Central and East Africa,

and a northern belt from Senegambia through Lake Chad to Abyssinia, while it extends to the Atlantic coast from Angola to Damara Land. divided, but it exhibits throughout the main features of Central This extensive district may doubtless be further sub. African zoology as distinct from that of West and South Africa. Its zoological characters are negative rather than positive, as it has very few peculiar groups; but all the great African Mammalia abound, and a greater variety of antelopes are found here than in the other sub-regions.

The West African or forest sub-region extends from the Gambia to the Congo, and inland to the sources of the Nile and the western watershed of the great lakes. It is characterized generally by a luxuriant forest-vegetation, and it possesses many peculiar animal forms. Here we find the gorilla and chimpanzee, a great variety of monkeys, and two peculiar genera of lemurs, as well as some remarkable genera of Insectivora, Viverride, and Tragulida. It is the home of the gray parrots (Psittacus), the typical plaintain(Pitta), and many peculiar genera of passerine birds. caters (Musophaga), one of the Eastern group of ground thrushes Reptiles are very abundant, no less than 13 genera of snakes and 3 of lizards being peculiar to this sub-region. As is always the case in tropical forest-districts, insects are especially numerous, of large size and

brilliant colours.

We find

The South African or extra-tropical sub-region, though quite open to the central districts and to a large extent overrun with the same fauna, yet presents so many peculiarities as to indicate, probably, a former southward extension of the continent. here 3 peculiar genera of Viverride, the remarkable Proteles, peculiar Canide and Mustelidae, many peculiar rodents, including Bathyerges (one of the mole-rats), Petromys (one of the spiny-rats). and Pedetes (the Cape-hare). There are also some peculiar genera of birds, among which are a sun-bird, 2 weaver-birds, 3 larks, and a curious woodpecker (Geocolaptes). Reptiles are still more pecu. liar, 4 genera of snakes and 10 of lizards being almost or quite restricted to this limited district. Insects, too, are very remarkable, there being 7 peculiar genera of butterflies, and a host of beetles which are either quite peculiar or have their nearest allies in Madagascar, in India, or America. This remarkable and isolated fauna must be considered, in connection with the wonderful Capo flora-so much richer and more isolated than that of any other part of Africa-as indicating important changes in the past history of this part of the globe.

III. The Oriental Region.-The Oriental region is wholly tropical, but is of smaller extent than the Ethiopian. It is very largely covered with forest-vegetation, and is much broken up into islands and promontories, conditions so favourable to animal life as fully to compensate for its smaller area.

In the larger Mammalia there are many resemblances between the Oriental and Ethiopian regions. Both have anthropoid apes, elephants, rhinoceroses, large felines, buffaloes, and an abundance of civets. But the Oriental region abounds in deer and bears, it has many remarkable Insectivora, the Malay tapir, and many wild cattle. It has also a great number of characteristic forms of life. It has 6 peculiar genera of apes, and 3 of lemurs; 5 of Insectivora, among which are two peculiar families, Galeopithecida and Tupaiida; 12 of Viverrida; 1 one of Canidae; 5 of Mustelida; 2 of Ursidae; 1 of Tragulida; 1 of Cervidae; 4 of Bovidae; and 5 of Rodents.

Tits,

The birds of this region are exceedingly abundant, varied, and remarkable. Among them are 3 peculiar families of passerine birds-the hill-tits (Liotrichidae), the green bulbuls (Phyllornithidae), and the gapers (Eurylamidœ); while the babblers (Timaliida), the fruit-thrushes (Pycnonotida), and the king-crows (Dicruridae) are far more abundant than in the adjacent regions. flycatchers, crows, sun-birds, starlings, kingfishers, pigeons, and pheasants are also very abundant, and are represented by many remarkable forms. More than 340 genera .of land-birds inhabit the region, of which number 165 are peculiar to it. Reptiles are very abundant. Three small families of snakes are peculiar, and there are a large number of peculiar genera both of snakes and lizards.

Insects are exceedingly varied and beautiful, especially in the Himalayas and in the Malay islands. Among butterflies the Danaida are very abundant, while the true Papilios are perhaps finer than in any other part of the

world. Among beetles the Lucanida, Cetoniida, and Buprestida are especially remarkable, while the elegant Longicorns have their full quota of eurious and beautiful forms. Subdivisions of the Oriental Region.-These are tolerably well marked, though very unequal in extent and productiveness. The Himalayan slopes with all the Indo-Chinese countries form the chief and most typical part of the region. Here are the greatest variety of Mammalia and birds, and almost all the more important groups are represented. Three genera of Mammalia and 44 of birds are peculiar to this sub-region. The Malay Peninsula, with the larger Malay islands, as far as Java, Borneo, and the Philippines, form a sub-region which has much in common with the last, and is almost equally rich, and in some groups even richer and more peculiar. Thus it has no less than 14 genera of Mammalia and more than 40 genera of birds which are wholly peculiar to it, among which are such interesting forms as the orang-utans (Simia), the spectre-lemur (Tarsius), the flyinglemur (Galeopithecus), the feather-tailed tupaia (Ptilocerus), the sunbear (Helarctos), and the magnificent argus-pheasants (Argusianus). About an equal number of genera are common to the Malayan and the Indo-Chinese sub-regions, but are not found elsewhere; so that the two have much in common, and together comprise nearly all that is most remarkable and beautiful of the Oriental fauna.

are such remarkable forms as the Paradise-birds (Paradi sæida), the honey-suckers (Meliphagidae), the lyre-birds (Menurida), the cockatoos (Cacatuida), the lories (Trichoglos side), the mound-builders (Megapodiida), and the cassowaries (Casuariida). Among the important groups which are entirely wanting in Australia are the barbets (Megalamida), the woodpeckers (Picide, otherwise cosmopolitan), the trogons (Trogonidae), and the pheasants (Phasianida). The ties than the birds; but a large proportion of the genera reptiles, as in most other cases, offer less marked peculiariare peculiar, and there are even 3 peculiar families of lizards, as well as the singular Hatteria of New Zealand, which constitutes not only a separate family but a new order of reptiles. The Amphibia and fresh-water fishes present a corresponding amount of peculiarity; and the recent discovery of the genus Ceratodus (the mud-fish) is very interesting, since its nearest allies appear to have lived early in the Secondary period, while other members of the same group are found isolated in the rivers of tropical Africa and America.

Ceylon and Southern India are somewhat more interesting, as they possess some peculiar forms, and others in common with the Malay islands. Among the former is Loris, a peculiar lemur; and there is a peculiar genus of Muride, as well as one or two peculiar genera of birds. There are also several peculiar species of monkeys, and the Malayan genus Tupaia; while among birds we find Malayan forms of cuckoos and Timaliida. The reptiles, however, best characterize this sub-region, as it possesses an entirely peculiar family of snakes (Uropeltida), consisting of 5 genera and 18 species, as well as 4 other peculiar genera of snakes. There are also many peculiar genera of lizards belonging to the Agamida and Acontiada, and 3 peculiar genera of tailless Batrachia. The insects also offer some remarkable cases of Malayan affinity, the genus Hestia (or spectre-butterflies) being found in Ceylon only beyond the Malay islands; while 6 genera of Malayan Longicorns and the wingless Tricondyla belonging to the Cicindelida, are in the same category. The combination of so many peculiarities justifies the separation of Ceylon and a portion of Southern India as a distinct Oriental sub-region.

IV. The Australian Region.-On entering this region we meet with such a radical change in all the higher forms of life, that the zoologist seems to have got into a new world. Even the Austro-Malay islands, though differing in no way in climate or luxuriance of vegetation from the Indo-Malay islands to the west of them, exhibit this change in an almos equally marked degree. With the exception of Celebes, which is a debatable land hardly belonging to either region, the other islands only posssess a few deer and pigs to represent the host of varied Mammalia-from the elephant and tapir to the squirrel and monkey-which characterize every part of the Oriental region to its extreme south-eastern limits in Java and Borneo. In place of these we have Marsupials only, in great variety in the extensive country of Australia and less abundantly in the islands; and besides these, only those flying mammals-the bats, which can traverse the ocean, and the smallest forms of rodents, the mice-which may be occasionally carried by floating trees or other accidental means across narrow arms of the sea. There are 5 distinct families and 33 genera of Australian Marsupials, as well as 2 families and genera of the still more lowly-organized Monotremata which comprise the anomalous Ornithorhynchus and Echidna.

Birds, as might be expected, are not so excessively peculiar, a large number of almost cosmopolitan families extending into Australia; yet there are no less than 16 families altogether characteristic of the region, among which

Subdivisions of the Australian Region.-Besides the Australian continent, which is by far the richest and most important part of the region, there are three groups of islands which have cach some distinctive peculiarities. These are the Austro-Malay islands, comprising New Guinea, the Moluccas, and the Tiuor group; the Pacific islands; and the New Zealand group. The first is very rich, especially in birds and insects while the other two are exceed. ingly poor.

The Austro-Malayan sub-region, of which New Guinea is the central mass, is comparatively poor in Mammalia, only 9 genera of marsupials being yet known, 6 of them being peculiar, with pigs, a few mice, and some deer (perhaps introduced) in the Moluccas. Birds are far more numerous, the Paradise birds and the true crimson lories being peculiar to the sub-region, while more than 40 genera of land-birds are confined to it. It is exceptionally rich in peculiar forms of flycatchers, honey-suckers, kingfishers, cockatoos, and pigeons; and its birds are generally characterized by a brilliancy of plumage far exceeding that which prevails in the surrounding regions. The insects exhibit a similar brilliancy, some sub-region. of the finest butterflies and beetles in the world belonging to this

Directly we pass east of the Solomon Islands we enter upon one of the poorest zoological regions in the world in proportion to its being in the land-shells, which are very largely developed and very extent and luxuriant vegetation, the only exception to this poverty peculiar. Indigenous Mammalia are wholly wanting. Birds are very scarce, no more than about 150 species being known from the numerous islands scattered over 5000 miles of the Pacific, while there are only about a dozen peculiar genera. Reptiles are more numerous than might be expected, considering the wide extent of ocean separating many of the islands. There are 14 genera of lizards, of which 6 are peculiar, but few extend eastward of the Samoa Islands. Snakes are much less abundant, and none are found east of the Fiji Islands. Insects are exceedingly scarce, and of little interest. The New Zealand group, though situated beyond the tropics and very remote from other lands, yet possesses a more ample and more interesting fauna. If we except two bats, mammals are wanting; but birds are tolerably abundant, and are very peculiar and inpeculiar. Twelve of these are passerine birds, chiefly Meliphagida teresting. There are 34 genera of land-birds, of which 16 are and Sturnida, with Nestor and Stringops, peculiar genera of parrots, and the extraordinary wingless Apteryx. Reptiles are few. There are a few lizards, with one peculiar genus, but no snakes. The anomalous Hatteria has been already mentioned. There is also one fresh-water fishes, one genus belonging to the Salmonido, a family There are some interesting frog belonging to a peculiar genus. not occurring elsewhere in the southern hemisphere; and there are several species allied to Souta American fishes.

Insects are very few, and generally of small size and inconspi cuous colours. Many of them are peculiar, but they have mostly affinities with Australian groups, or with those from the Oriental region.

The Mammalia are as abundant and varied as in any other countries except Africa and tropical Asia; but the region is characterized by poverty in the more highly organized forms, with a corresponding abundance of lower types. Monkeys are abundant, but all belong to two peculiar families-Cebidae and Hapalida-different in structure and of a somewhat lower organization than those of the Old World. About half of them have powerfully prehensile tails, a character unknown among the monkeys of the eastern hemisphere. Bats are very numerous, and one extensive family-the Phyllostomide, or vampyrebats-is peculiar. Insectivora are unknown in South America, but one peculiar genus occurs in the larger Antilles, and a few shrews in Central America. Carnivora are but moderately numerous, the Civet family being entirely wanting, as are the bears, with the exception of a solitary species in Chili. There is, however, one peculiar family-the Procyonide-which extends over North America as well. A marked feature is the excessive scarcity of the great family of the Ungulata, or hoofed animals. There are no wild cattle, sheep, goats, antelopes, horses, or rhinoceroses; and only a very few species of tapirs, peccaries, llamas, and deer in their place. Coming to the small and feeble Rodents, however, we find a great abundance and variety of forms, including the largest on the globe.

Five families are peculiar or nearly so,

The

the chinchillas and the cavies being the most important, while all the genera, except Sciurus and Lepus, are peculiar to the American continent. We now come to the Edentata, the most imperfectly organized and the most characteristic of the Neotropical mammals. There are twelve genera belonging to the three families of the sloths (Bradypodido), the armadillos (Dasypodide), and the ant eaters (Myrmecophagidae). Lastly, we have the Marsupial opossums, which range far over temperate North America, but are most abundant in the tropical regions of South America.

In birds the Neotropical region is wonderfully rich. It possesses far more distinct genera and species than any other region, and it has 24 entire families peculiar to it, while the region which comes next in speciality and isolation as regards this order-the Australian-has only 16. Most of these peculiar families are, however, of a somewhat low grade of organization, and it is these which abound most in genera and species and give a special feature to the ornithology of the country. These peculiarly American families (for some of them range into North America) are the tyrant fly-catchers (Tyrannida), the manakins (Pipride), the chatterers (Cotingidae), the plant-cutters (Phytotomidae), the tree-creepers (Dendrocolaptide), the ant-thrushes (Formicariidae), and the wren-thrushes (Pteroptochida). All these have a deficiency in the singing-muscles of the throat, and they comprise more than 200 genera. Then, among the Picaria, which are low though wide-spread order, we have the toucans (Rhamphastida), the puff-birds (Bucconidae), the jacamars (Galbulida), the motmots (Momotide), and the humming birds (Trochilida), comprising 140 genera. The only

a

Carebida), the greenlets (Vireonidae), the hang-nests (Icterida), and the tanagers (Tanagridae), comprising in all 82 genera. The most highly organized groups of birds, and those which are most abundant in the eastern hemisphere, such as crows, starlings, thrushes, warblers, and flycathers, are either scarce or entirely wanting. Finches are numerous, aз are parrots. Among game-birds the higher types, as the grouse (Tetraonida), are scarce; while the more lowly-organized curassows (Cracide) and tinamous (Tinamide) are much more abundant and more widely distributed over the whole region. Among the wading groups (Gralla), which are decidedly of low organization, there are 6 peculiar and very isolated families, the most remarkable being the Cariamida, the Psophiide (trumpeters), the Eurypygide (sun-bitterns), and the Palamedeidae (horned-screamers). The very low struthious type is represented by the American ostriches (Rhea). Reptiles are also very abundant in the Neotropical region, and there are inany peculiar groups. Snakes are represented by peculiar genera only, the families being almost always widely and often universally distributed in warm regions; lizards are more restricted in their range, and no less than 5 families are peculiar to the region, while 9 are found only in the American continent. All are of very small extent except two, the Teide and Iguanida, which are very numerous, and comprise the most characteristic American lizards. There are also 4 peculiar families of tailless Batrachians, the most popularly known being the Pipida, which contains the remarkable Surinam toad.

Fresh-water fishes are probably more abuudant and varied than in any other region. Three entire families and, several sub-family groups are peculiar, and the enormous forest-bordered rivers and extensive tracts of annually flooded woodland have led to the development of special groups of fruit-eating fishes, which, as articles of food, are not only unsurpassed but altogether unequalled in any other part of the globe. Fresh-water rays (Trygonida) and electric eels (Gymnotida) are also peculiar to Neotropical rivers, and there are an immense variety of Siluride, Characinidae, and Cyprinodontide. It is reported that Professor Agassiz obtained more than a thousand species of fishes in the Amazon aloue; but, although this may be exaggeration, there is no doubt that a still greater number exists in that wonderful river and its tributaries.

The insects of tropical America are so inexhaustible in their variety, and so wonderful in their beauty, that it is hopeless to attempt to give an adequate idea of them. Tho butterflies are far more abundant and more gorgeous than in any other region, and their variety may be imagined from the fact that the peculiar genera are nearly equal in number to those of the rest of the world. The beetles, though very abundant, are not so clearly preponderant over those of all other regions. The stag-beetles (Lucanida) and rose-chafers (Cetoniida) are somewhat poorly developed; but all the other large families are very abundant, and comprise many forms of extreme beauty and interest. Such are the genera Agra among Carabidae, Pyrodes among Longicorns, and Entimus among Curculionidae. Land-shells equally surpass those of all other regions, but this is owing to the exceptional richness of the West Indian islands, the continent of America being by no means extraordinarily rich in this class of animals.

Subdivisions of the Neotropical Region.-The manner in which this region may be most naturally and conveniently divided for zoological purposes is doubtful. Almost the whole of tropical South America (excluding only the higher Andes south of Chimborazo and the dry plain to the west) forms a compact area in which all the more characteristic Neotropical animal groups are developed in their highest luxuriance. This, however, falls natu

rally into three subdivisions, which may be generally indicated as Guiana, Brazil, and the Eastern Andes, each of which is characterized by a great number of peculiar generic types. These three areas are considered by Professor Newton (in his article BIRDS in this work) to be sub-regions, each equivalent to the whole of south temperate America, and to the tropical part of North America, which may be termed the Mexican sub-region. But each of these latter may be also divided. South temperate America consists of a western and an eastern division, each with many distinct groups, while the southern parts of Central America differ greatly from the northern; and all these subdivisions may be considered as provinces of their respective sub-regions. It seems better, therefore, for the purposes of such a general sketch as the present, to consider the tropical parts of South America, as above limited, to be one great sub-region, characterized by possessing a large proportion of the animal forms of the whole region. It will therefore only be necessary to indicate in what way the other sub-regions differ from this. The Chilian sub-region, or temperate South America as above defined, is well characterized by its exclusive possession of the family of the Chinchillida (comprising three genera) and the genus Auchenia (the llamas and alpacas), the only representatives of the Camelidae in the New World. It also has a peculiar form of bear, several peculiar genera of rodents, and two peculiar forms of armadillos. Among birds it has the curious plant-cutters (Phytotomide), a peculiar family of waders (Thinocorida), about 26 peculiar genera of passerine birds-1 of parrots, 2 of pigeons, and 2 of tinamous. It also possesses the American ostriches (Rhea), and 3 peculiar genera of plovers. The reptiles are usually of tropical genera, but a few are peculiar. Many of the fresh-water fishes are of peculiar genera, but there are some Australia forms, and even one species (Galaxias attenuatus) is common to New Zealand, Tasmania, and Patagonia.

Among insects alone we meet with indications of a decided affinity for forms of the north temperate zone. There are several

The

butterflies allied to Brebia, an Arctic genus, and others belonging to the northern genera Hipparchia, Argynnis, and Coli mass of the butterflies, however, are purely Neotropical. Of the beetles some are Australian, but the majority are allied to Neotropical forms; yet among the Carabida, or carnivorous groundbeetles, there are many truly northern genera, such as Carabus, Anchomenus, Trechus, &c., whose presence supports the theory of a migration along the Andes from the northern hemisphere. (See Wallace's Geographical Distribution of Animals, vol. ii. pp. 44 48.)

In tropical North America, or the Mexican sub-region, we find far less peculiarity. The southern portion from Panama to Nicaragua can hardly be separated zoologically from the adjacent parts of South America, while further north the chief difference consists in the absence of many typical Neotropical groups, and the appear ance of a few which more especially characterize the Nearctic region. A peculiar form of tapir (Elasmognathus) inhabits Central America, with one or two peculiar genera of rodents; while such northern forms as Sorez, Vulpes, Lepus, and Pteromys range as far south as Guatemala. Birds are more especially characteristic, since the sub-region possesses no less than 37 peculiar genera of land birds; but many Neotropical groups are absent. The most im portant of these deficiencies are the Pteroptochido, and the subfamilies Furnariina, Conophagina, and Rupicolina, as well as most of the peculiar groups of waders. In place of these are found tits (Parida), creepers (Certhiidae), waxwings (Ampelida), and turkeys (Phasianida) from the north. The fresh-water fishes as well as the insects are almost wholly Neotropical in character, but exhibit a considerable amount of speciality.

There remains the West Indian Islands or the Antillean subregion, which in the amount of isolation and speciality it exhibits is better marked than any other part of the region. The Mammalia are few but very interesting, as is usually the case in islands separated from continents by very deep sea. There are no monkeys, Carnivora, Ungulates, or Edentata, the only orders represented being the Insectivora and the Rodentia. The former, which is unknown in South America, is here represented by a peculiar genus, Scienodon, belonging to a family, Centetida, only found elsewhere in Madagascar. The Rodents consist of two very peculiar generaCapromys and Plagiodontia belonging to a family which is especially South American, with a peculiar mouse, and an agouti (Day procta) in the lesser Antilles. The birds are far more abundant, about 200 resident species being known, besides a large number of migrants from the United States. These belong to 95 genera, of which about one-third are peculiar. The only entirely peculiar family group is that of the todies (Todide), small and elegant birds whose nearest allies are the South American motmots and jacamars. The reptiles are not very well known, but they seem tolerably numerous, and mostly allied to South American groups; and the same remark applies to the fresh-water fishes. Insects are not very abundant, and beetles seem especially scarce considering the luxuriant vegetation of most of the islands. In land-shells, however, the very reverse is the case, the Antilles being more productive than

any other part of the world. The number of species of West Indian land-shells is equal to that of the entire continent of America, while the number of genera is greater. No less than 11 of the genera are peculiar, a very unusual degree of speciality considering the extensive range of most of the genera of land-mollusca.

VI. The Nearctic Region. This comprises all temperate North America; and its peculiar fauna is best represented in the United States, and especially in that portion extending from the Mississippi valley to the Atlantic. It is allied both to the Neotropical and the Palearctic regions, but it also possesses a considerable number of peculiar or characteristic forms. Among Mammalia it possesses 3 peculiar genera of moles, 2 of weasels, 2 of hollow-horned ruminants Antilocapra (the prong-buck) and Aplocerus (the mountain goat or antelope)-and a number of Rodents, among which the most peculiar are the Saccomyidae or pouched rats. Of those groups which are more peculiarly Neotropical it has skunks (Mephitis), racoons (Procyon), and opossums (Didelphys). The number of Palearctic groups is greater, the more important being lynxes, wolves, martens, bears, elks, bisons, sheep, flying-squirrels, and marmots.

Of birds there are between forty and fifty genera which are peculiar or highly characteristic. Most of them belong to the passerine families, the wood-warblers (Mniotiltide) and the finches (Fringillida) being especially rich in peculiar groups; and there are also a few among the thrushes, wrens, crows, hang-nests, woodpeckers, grouse, turkeys (Meleagris), the ruffed grouse (Cupidonia, &c.), and some other families. Among the larger birds the and the crested partridges (Oreortyx, &c.) are the most remarkable.

Reptiles seem to be more numerous than in the Palearctic region. About a dozen genera of snakes are peculiar or characteristic, the most remarkable being the well-known rattle-snakes (Crotalus). Among lizards the so-called "glass-snake" (Ophisaurus) is a peculiar form analogous to our slow-worm; while the horned-lizards (Phrynosoma) and many other genera of Iguanidæ are peculiar. Fresh-water fishes are exceedingly numerous and highly peculiar, there being no less than five (or, according to recent authors, eight) peculiar families, and a large number of peculiar genera. The perches and their allies (Percida, Ichthelida, Labracidae, and Etheostomida), the carps (Cyprinida), the suckers (Catostomida), and the catfish (Silurida) are the most abundant groups.

In insects the Nearctic region is not remarkably rich or very peculiar. Its butterflies, though tolerably abundant, belong for the most part to well-known European groups with a small infusion of Neotropical forms in the Southern States. The same may be said of its Coleoptera. Landshells are tolerably plentiful but not strikingly peculiar ; the Alleghany district being the most productive, and possessing a large number of peculiar species. In freshwater shells North America surpasses every other part of the globe, considerably over a thousand species, most of them Unionida or fresh-water mussels, having been described.

Subdivisions of the Nearctic Region.-Owing to the researches of American zoologists these have been ascertained with tolerable accuracy, and may be termed respectively the Californian, the Rocky Mountain, the Alleghany, and the Canadian sub-regions.

The western or Californian sub-region comprises the narrow tract between the Sierra Nevada and the Pacific, not including Lower California, but extending northward into British Columbia to about 53° N. lat. It is characterized by a few very peculiar forms, and by a greater infusion of South American types than are found in similar latitudes on the east coast. Among Mammals Macrotus, a genus of vampyre bats; among birds a cuckoo of the genus Geococcyx, and 2 genera of humming-birds (Selasphorus and Atthis); and among reptiles Lichanotus, a snake allied to the boas, are Neotropical forms. California has also five or six peculiar genera of mammalia,-Urdrichus, one of the moles, and Haploodon, forming a distinct family of Rodents, being the most remarkable; while

Chamaa, forming a distinct family allied to the wrens, is the most | interesting and peculiar bird.

The central or Rocky Mountain sub-region extends eastward from the Sierra Nevada across the Rocky Mountains to a line a little eastward of the 100th meridian, where a marked change in the climate, vegetation, and animal life is found to occur. To the north it is bounded by the great Canadian forest-zone on the upper Saskatchewan, while southwards it extends into Texas and Lower California and along the line of highlands to beyond the city of Mexico. This sub-region is characterized by many peculiar animals, some of which are closely allied to Palearctic types-as the so-called buffalo (Bison americanus), the big-horned sheep (Ovis montana), the glutton (Gulo arcticus), and the pika (Lagomys princeps); while others are altogether distinct forms, as the prong-horn (Antilocapra) and the antelope or mountain goat (Aplocerus). Of Palearctic forms of birds it has two peculiar genera of grouse (Centrocercus and Pediocetes), and the Arctic wood-pecker and ptarmigan. More especially Nearctic are a genus of wrens (Salpinctes) and some peculiar genera of finches and crows. The Nearctic pouchedrats (Saccomyidae) are abundant.

The eastern or Alleghany sub-region comprises the country to the east of the last, and as far north as Wisconsin and the southern parts of Canada. It contains examples of all that is most characteristic in Nearctic zoology, and has besides a few peculiar groups. Of these the most noteworthy is the star-nosed mole (Condylura), and anong birds the passenger-pigeon (Ectopistes) and a few groups of wood-warblers and finches. The reptiles are more peculiar, as there are several genera of snakes, including two of Homalopsida and two of rattle-snakes, which hardly extend beyond it. Among lizards the glass-snake (Ophisaurus) is peculiar, and no less than four genera of tortoises are almost or quite confined to the subregion. Here, too, are found the peculiar Amphibia for which North America is so remarkable, such as the two genera of the Sirenida (Siren and Pseudobranchus), Menobranchus allied to the Proteus of Europe, Amphiuma, an eel-like creature with four rudimentary feet constituting a distinct family, and three peculiar genera of salamanders (Salamandrida). Fishes, too, are very abundant, and several of the peculiar North American forms are confined to this sub-region; such are the pirate-perch (Aphredo derus), the cave-fishes (Amblyopsida), the trout-perches (Percopsida), several genera of sun-fishes (Ichthelida), and many others. The sub-Arctic or Canadian sub-region has very few distinctive features, but it serves at once to connect and separate the other three regions which almost merge into it. The musk-sheep (Ovibos) is almost the only form peculiar to it, though this is more properly Arctic. Many of the most characteristic Nearctic animals, such as Condylura and Mephitis, only just enter its southern borders, while most of the Arctic forms are more abundant here than further south. Great numbers of birds migrate here in summer from the Southern States and Mexico; while a few especially Palearctic groups (as Budytes, Phylloscopus, and Pyrrhula), which do not occur elsewhere in North America, have been found in Alaska. The scanty fauna of Greenland shows that it forms a part of this sub-region.

DISTRIBUTION OF THE HIGHER ANIMALS DURING THE TERTIARY PERIOD.

Before we proceed to other divisions of our subject, we shall find it useful to consider briefly the geographical relations of the Tertiary and post-Tertiary faunas to that which now exists, as we shall thereby arrive at a better comprehension of the true nature of zoological regions, and the meaning of the diverse and complex relations that exist between them.

Post-Tertiary Faunas.—Researches in alluvial clays and gravels, cave-earths, and other superficial deposits have made known to us very completely the character of the fauna which immediately preceded that now existing, and which lived at the close of the glacial period and in the era of prehistoric man. We find, as might be expected, that a considerable number of the Mammalia were identical with living species, but along with these we almost always find a number of extinct forms, some closely related to living species in the same district, while others seem to indicate migration and a change of climate, by their resemblance to species which now only live further north or south. More extraordinary is the fact, that many of these recently extinct forms were of huge size as compared to any now living, often reminding us of the bulkiest inhabitants of the tropics or of those huge animals which we

associate with an earlier condition of the earth's surface. Thus, in Europe during the post-Tertiary period, the reindeer, the glutton, and the Tartarian antelope inhabited France, along with powerful felines allied to the existing lion. At the same time elephants and rhinoceroses of several species roamed all over Europe; and at one period hippopotami ranged as far north as the Thames, while tho European beaver was replaced by a much larger species. In North America about the same time we find extinct. lions, horses, tapirs, and camels, with bisons and musksheep, as well as elephants and mastodons; and along with these, three genera of gigantic sloths as large as rhinoceroses and elephants,-forming an assemblage of large Mammalia wonderfully different.from that which now exists in the same country. In South America we find that there were larger monkeys than any now living, together with lions, bears, horses, tapirs, and antelopes, as well as mastodons, and a tree-porcupine as large as a peccary. Here also were armadillos as large as a rhinoceros, and huge sloths as in North America but of more varied kinds. Even in Australia very similar phenomena cccur. Extinct wombats as large as tapirs, kangaroos the size of elephants, and a phalanger nearly as large as a lion have been found in cave-deposits, along with a number of other forms more nearly like those now living. But in this case all are Marsupials or Monotremes, and there is no sign of any migration from other lands, which indeed, owing to the insular nature of the country, we could hardly expect. Again, in New Zealand and Madagascar we have a similar phenomenon presented to us by the great extinct terrestrial from the conditions under which their remains are found, birds-the "moas," the "dodos," and the Epyornis, which, have evidently not long ceased to exist.

It appears then that in all parts of the world where we have been able to obtain the requisite information, the period which immediately preceded that in which we live was characterized by great movements or migrations of the higher animals where that was possible; and everywhere, by the extinction of a variety of huge animals belonging to almost every order of Mammalia and to several orders of birds, many of which are now totally unrepresented on the globe.

Tertiary Faunas, and their Geographical Relations with those of the six Zoological Regions.-When we go back to the late and middle Tertiary deposits, we find a series of remains of the higher animals which exhibit yet more remarkable changes of distribution. Various parts of central and southern Europe, for example, were then inhabited by animals which now form the most characteristic features of Ethiopian and Oriental zoology-such as apes and monkeys, lions and hyænas, horses, tapirs, elephants, rhinoceroses, giraffes, and various antelopes; and along with these a number of extinct ancestral forms of many of the same groups. Among birds, too, we find the eastern jungle-fowl, the edible-nest swift, and the trogon, along with African parrots and plantain-eaters. In the Miocene beds of Northern India are found such typical African groups as the hippopotamus and giraffe.

Now geology teaches us, that in the Eocene, or earliest portion of the Tertiary epoch, a continuous arm of the sea extended from the Bay of Bengal to the Atlantic Ocean, cutting off the peninsula of India and Central Africa from the Palearctic region; and it is therefore highly probable that, when this sea-bed became dry land, the various large Mammalia now so characteristic of Africa entered it for the

1 See Mr Searles V. Wood, jun., "On the Form and Distribution of the Land Tracts during the Secondary and Tertiary Periods respectively, and on the effect upon Animal Life which great changes in Geographical Configuration have probably produced" (Philosophical Magazine, 1862).