The Geographical Distribution of Animals/Chapter 12
THE ORIENTAL REGION.
This region is of comparatively small extent, but it has a very diversified surface, and is proportionately very rich. The deserts on the north-west of India are the debatable land that separates it from the Palæarctic and Ethiopian regions. The great triangular plateau which forms the peninsula of India is the poorest portion of the region, owing in part to its arid climate and in part to its isolated position; for there can be little doubt that in the later Tertiary period it was an island, separated by an arm of the sea (now forming the valleys of the Ganges and Indus) from the luxuriant Himalayan and Burmese countries. Its southern extremity, with Ceylon, has a moister climate and more luxuriant vegetation, and exhibits indications of a former extension southwards, with a richer and more peculiar fauna, partly Malayan and partly Mascarene in its character. The whole southern slopes of the Himalayas, with Burmah, Siam and Western China, as well as the Malay peninsula and the Indo-Malay islands, are almost everywhere covered with tropical forests of the most luxuriant character, which abound in varied and peculiar forms of vegetable and animal life. The flora and fauna of this extensive district are essentially of one type throughout; yet it may be usefully divided into the Indo-Chinese and the Malayan sub-regions, as each possesses a number of peculiar or characteristic animals. The former sub-region, besides having many tropical and sub-tropical types of its own, also possesses a large number of peculiarly modified temperate forms on the mountain ranges of its northern boundary, which are wholly wanting in the Malayan sub-region. The Philippine islands are best classed with the Indo-Malay group, although they are strikingly deficient in many Malayan types, and exhibit an approach to the Celebesian division of the Austro-Malay sub-region.
Zoological Characteristics of the Oriental Region.—The Oriental Region possesses examples of 35 families of Mammalia, 71 of Birds, 35 of Reptiles, 9 of Amphibia, and 13 of Fresh-water Fishes. Of these 163 families, 12 are peculiar to the region; namely, Tarsiidæ, Galeopithecidæ, and Tupaiidæ among Mammalia, while Æluridæ, though confined to the higher Himalayas, may perhaps with more justice be claimed by the Palæarctic region; Liotrichidæ, Phyllornithidæ, and Eurylæmidæ among birds; Xenopeltidæ (extending, however, to Celebes), Uropeltidæ, and Acrochordidæ among reptiles; Luciocephalidæ, Ophiocephalidæ and Mastacembelidæ among fresh-water fishes. A number of other families are abundant, and characteristic of the region; and it possesses many peculiar and characteristic genera, which must be referred to somewhat more in detail.
Mammalia.—The Oriental region is rich in quadrumana, and is especially remarkable for its orang-utans and long-armed apes (Simia, Hylobates, and Siamanga); its abundance of monkeys of the genera Presbytes and Macacus; its extraordinary long-nosed monkey (Presbytes nasalis); its Lemuridæ (Nycticebus and Loris); and its curious genus Tarsius, forming a distinct family of lemurs. All these quadrumanous genera are confined to it, except Tarsius which extends as far as Celebes. It possesses more than 30 genera of bats, which are enumerated in the lists given at the end of this chapter. In Insectivora it is very rich, and possesses several remarkable forms, such as the flying lemur (Galeopithecus); the squirrel-like Tupaiidæ consisting of three genera; and the curious Gymnura allied to the hedgehogs. In Carnivora, it is especially rich in many forms of civets (Viverridæ), possessing 10 peculiar genera, among which Prionodon and Cynogale are remarkable; numerous Mustelidæ, of which Gymnopus, Mydaus, Aonyx and Helictis are the most conspicuous; Ælurus, a curious animal, cat-like in appearance but more allied to the bears, forming a distinct family of Carnivora, and confined to the high forest-districts of the Eastern Himalayas and East Thibet; Melursus and Helarctos, peculiar forms of bears; Platanista, a dolphin peculiar to the Ganges and Indus. Among Ruminants it has the beautiful chevrotain, forming the genus Tragulus in the family Tragulidæ; with one peculiar genus and three peculiar sub-genera of true deer. The Antilopinæ and Caprinæ are few, confined to limited districts and not characteristic of the region; but there are everywhere wild cattle of the genera Bibos and Bubalus, which, with species of Rhinoceros and Elephas, form a prominent feature in the fauna. The Rodents are less developed than in the Ethiopian region, but several forms of squirrels everywhere abound, together with some species of porcupine; and the Edentata are represented by the scaly manis.
Birds.—The families and genera of birds which give a character to Oriental lands, are so numerous and varied, that we can here only notice the more prominent and more remarkable. The Timaliidæ, represented by the babblers (Garrulax, Pomatorhinus, Timalia, &c.), are almost everywhere to be met with, and no less than 21 genera are peculiar to the region; the elegant fork-tailed Enicurus and rich blue Myiophonus, though comparatively scarce, are characteristic of the Malayan and Indo-Chinese faunas; the elegant little "hill-tits" (Liotrichidæ) abound in the same part of the region; the green bulbuls (Phyllornis) are found everywhere; as are various forms of Pycnonotidæ, the black and crimson "minivets" (Pericrocotus), and the glossy "king-crows" (Dicrurus); Urocissa, Platylophus and Dendrocitta are some of the interesting and characteristic forms of the crow family; sun-birds (Nectariniidæ) of at least three genera are found throughout the region, as are the beautiful little flower-peckers (Dicæidæ), and some peculiar forms of weaver-birds (Ploceus and Munia). Of the starling family, the most conspicuous are the glossy mynahs (Eulabes). The swallow-shrikes (Artamus) are very peculiar, as are the exquisitely coloured pittas (Pittidæ), and the gaudy broad-bills (Eurylæmidæ). Leaving the true Passeres, we find woodpeckers, barbets, and cuckoos everywhere, often of peculiar and remarkable forms; among the bee-eaters we have the exquisite Nyctiornis with its pendent neck-plumes of blue or scarlet; brilliant kingfishers and strangely formed hornbills abound everywhere; while brown-backed trogons with red and orange breasts, though far less frequent, are equally a feature of the Ornithology. Next we have the frog-mouthed goatsuckers (Batrachostomus), and the whiskered swifts (Dendrochelidon), both wide-spread, remarkable, and characteristic groups of the Oriental region. Coming to the parrot tribe, we have only the long-tailed Palæornis and the exquisite little Loriculus, as characteristic genera. We now come to the pigeons, among which the fruit-eating genera Treron and Carpophaga are the most conspicuous. The gallinaceous birds offer us some grand forms, such as the peacocks (Pavo); the argus pheasants (Argusianus); the fire-backed pheasants (Euplocamus); and the jungle-fowl (Gallus), all strikingly characteristic; and with these we may close our sketch, since the birds of prey and the two Orders comprising the waders and swimmers offer nothing sufficiently remarkable to be worthy of enumeration here.
Reptiles.—Only the more abundant and characteristic groups will here be noticed. In the serpent tribe, the Oligodontidæ, a small family of ground-snakes; the Homalopsidæ, or fresh-water snakes; the Dendrophidæ, or tree-snakes; the Dryiophidæ, or whip-snakes; the Dipsadidæ, or nocturnal tree-snakes; the Lycodontidæ or fanged ground-snakes; the Pythonidæ, or rock-snakes; the Elapidæ, or venomous colubrine snakes (including the "cobras"); and the Crotalidæ, or pit-vipers, are all abundant and characteristic, ranging over nearly the whole region, and presenting a great variety of genera and species. Among lizards, the Varanidæ or water-lizards; the Scincidæ or "scinks;" the Geckotidæ, or geckoes; and the Agamidæ, or eastern iguanas; are the most universal and characteristic groups. Among crocodiles the genus Crocodilus is widely spread, Gavialis being characteristic of the Ganges. Among Chelonia, or shielded reptiles, forms of fresh-water Testudinidæ and Trionychidæ (soft tortoises) are tolerably abundant.
Amphibia.—The only abundant and characteristic groups of this class are toads of the family Engystomidæ; tree-frogs of the family Polypedatidæ; and several genera of true frogs, Ranidæ.
Fresh-water Fishes.—The more remarkable and characteristic fishes inhabiting the fresh waters of the Oriental region belong to the following families: Nandidæ, Labyrinthici, Ophiocephalidæ, Siluridæ, and Cyprinidæ; the last being specially abundant.
The sketch here very briefly given, must be supplemented by an examination of the tables of distribution of the genera of all the Mammalia and Birds inhabiting the region. We will now briefly summarize the results.
Summary of the Oriental Vertebrata.—The Oriental region possesses examples of 163 families of Vertebrata of which 12 are peculiar, a proportion of a little more than one-fourteenth of the whole.
Out of 118 genera of Mammalia 54 seem to be peculiar to the region, equal to a proportion of 9⁄20 or a little less than half. Of Land-Birds there are 342 genera of which 165 are peculiar, bringing the proportion very close to a half.
In the Ethiopian region the proportion of peculiar forms both of Mammalia and Birds is greater; a fact which is not surprising when we consider the long continued isolation of the latter region—an isolation which is even now very complete, owing to the vast extent of deserts intervening between it and the Palæarctic region; while the Oriental and Palæarctic were, during much of the Tertiary epoch, hardly separable.
Lepidoptera.—We can only glance hastily at the more prominent features of the wonderfully rich and varied butterfly-fauna of the Oriental region. In the first family Danaidæ, the genera Danais and Euplœa are everywhere abundant, and the latter especially forms a conspicuous feature in the entomological aspect of the country; the large "spectre-butterflies" (Hestia) are equally characteristic of the Malayan sub-region. Satyridæ, though abundant are not very remarkable, Debis, Melanitis, Mycalesis, and Ypthima being the most characteristic genera. Morphidæ are well represented by the genera Amathusia, Zeuxidia, Discophora, and Thaumantis, some of the species of which almost equal the grand South American Morphos. The Nymphalidæ furnish us with a host of characteristic genera, among the most remarkable of which are, Terinos, Adolias, Cethosia, Cyrestis, Limenitis, and Nymphalis, all abounding in beautiful species. Among the Lycænidæ are a number of fine groups, among which we may mention Ilerda, Myrina, Deudorix, Aphneus, Iolaus, and Amblypodia, as characteristic examples. The Pieridæ furnish many fine forms, such as Thyca, Iphias, Thestias, Eronia, Prioneris, and Dercas, the last two being peculiar. The Papilionidæ are unsurpassed in the world, presenting such grand genera as Teinopalpus and Bhutanitis; the yellow-marked Ornithopteræ; the superb "Brookiana;" the elegant Leptocircus; and Papilios of the "Coon," "Philoxenus," "Memnon," "Protenor," and especially the 'green-and-gold-dusted' "Paris" groups.
The Moths call for no special observations, except to notice the existence in Northern India of a number of forms which resemble in a striking manner some of the most remarkable of the above mentioned groups of the genus Papilio, especially the "Protenor" group, which there is reason to believe protected by a peculiar smell or taste like the Heliconias and Danaidæ.
Coleoptera.—The most characteristic Oriental form of the Cicindelidæ or tiger beetles, is undoubtedly the elegant genus Collyris, which is found over the whole region and is almost confined to it. Less abundant, but equally characteristic, is the wingless ant-like Tricondyla. Two small genera Apteroessa and Dromicidia are confined to the Indian Peninsula, while Therates only occurs in the Malayan sub-region.
The Carabidæ, or ground carnivorous beetles, are so numerous that we can only notice a few of the more remarkable and characteristic forms. The wonderful Mormolyce of the Indo-Malay sub-region, stands pre-eminent for singularity in the entire family. Thyreopterus, Orthogonius, Catascopus, and Pericallus are very characteristic forms, as well as Planetes and Distrigus, the latter having a single species in Madagascar. There are 80 genera of this family peculiar to the region, 10 of which have only been found in Ceylon.
Among the Lucanidæ, or stag-beetles, Lucanus, Odontolabris, and Cladognathus are the most characteristic forms. Sixteen genera inhabit the region, of which 7 are altogether peculiar, while three others only extend eastward to the Austro-Malayan sub-region.
The beautiful Cetoniidæ, or rose-chafers, are well represented by Rhomborhina, Heterorhina, Clinteria, Macronota, Agestrata, Chalcothea and many fine species of Cetonia. There are 17 peculiar genera, of which Mycteristes, Phædimus, Plectrone, and Rhagopteryx, are Malayan; while Narycius, Clerota, Bombodes, and Chiloloba are Indian.
In Buprestidæ—those elongate metallic-coloured beetles whose elytra are used as ornaments in many parts of the world—this region stands pre-eminent, in its gigantic Catoxantha, its fine Chrysochroa, its Indian Sternocera, its Malayan Chalcophora and Belionota, as well as many other beautiful forms. It possesses 41 genera, of which 14 are peculiar to it, the rest being generally of wide range or common to the Ethiopian and Australian regions.
In the extensive and elegant group of Longicorns, the Oriental region is only inferior to the Neotropical. It possesses 360 genera, 25 of which are Prionidæ, 117 Cerambycidæ, and 218 Lamiidæ;—about 70 per cent. of the whole being peculiar. The most characteristic genera are Rhaphidopodus and Ægosoma among Prionidæ; Neocerambyx, Euryarthrum, Pachyteria, Acrocyrta, Tetraommatus, Chloridolum, and Polyzonus among Cerambycidæ; and Cœlosterna, Rhytidophora, Batocera, Agelasta, and Astathes among Lamiidæ.
Of remarkable forms in other families, we may mention the gigantic horned Chalcosoma among Scarabæidæ; the metallic Campsosternus among Elateridæ; the handsome but anomalous Trictenotoma forming a distinct family; the gorgeous Pachyrhynchi of the Philippine Islands among Curculionidæ; Diurus among Brenthidæ; with an immense number and variety of Anthotribidæ, Heteromera, Malacoderma, and Phytophaga.
The Oriental Sub-regions.
The four sub-regions into which we have divided the Oriental region, are very unequal in extent, and perhaps more so in productiveness, but they each have well-marked special features, and serve well to exhibit the main zoological characteristics of the region. As they are all tolerably well defined and their faunas comparatively well-known, their characteristics will be given with rather more than usual detail.
I. Hindostan, or Indian Sub-region.
This includes the whole peninsula of India from the foot of the Himalayas on the north to somewhere near Seringapatam on the south, the boundary of the Ceylonese sub-region being unsettled. The deltas of the Ganges and Brahmaputra mark its eastern limits, and it probably reaches to about Cashmere in the north-west, and perhaps to the valley of the Indus further south; but the great desert tract to the east of the Indus forms a transition to the south Palæarctic sub-region. Perhaps on the whole the Indus may be taken as a convenient boundary. Many Indian naturalists, especially Mr. Blyth and Mr. Blanford, are impressed with the relations of the greater part of this sub-region to the Ethiopian region, and have proposed to divide it into several zoological districts dependent on differences of climate and vegetation, and characterized by possessing faunas more or less allied either to the Himalayan or the Ethiopian type. But these subdivisions appear far too complex to be useful to the general student, and even were they proved to be natural, would be beyond the scope of this work. I agree, however, with Mr. Elwes in thinking that they really belong to local rather than to geographical distribution, and confound "station" with "habitat." Wherever there is a marked diversity of surface and vegetation the productions of a country will correspondingly differ; the groups peculiar to forests, for example, will be absent from open plains or arid deserts. It happens that the three great Old World regions are separated from each other by a debatable land which is chiefly of a desert character; hence we must expect to find a resemblance between the inhabitants of such districts in each region. We also find a great resemblance between the aquatic birds of the three regions; and as we generally give little weight to these in our estimate of the degree of affinity of the faunas of different countries, so we should not count the desert fauna as of equal weight with the more restricted and peculiar types which are found in the fertile tracts,—in the mountains and valleys, and especially in the primeval forests. The supposed preponderance of exclusively Ethiopian groups of Mammalia and Birds in this, sub-region, deserves however a close examination, in order to ascertain how far the facts really warrant such an opinion.
Mammalia.—The following list of the more important genera of Mammalia which range over the larger part of this sub-region will enable naturalists to form an independent judgment as to the preponderance of Ethiopian, or of Oriental and Palæarctic types, in this, the most important of all the classes of animals for geographical distribution.
Range of the Genera of Mammalia which Inhabit the Sub-region of Hindostan.
|1. Presbytes||Oriental only.|
|2. Macacus||Oriental only.|
|3. Erinaceus||Palæarctic genus.|
|4. Sorex||Widely distributed.|
|5. Felis||Almost Cosmopolitan.|
|6. Cynælurus||Ethiopian and S. Palæarctic.|
|7. Viverra||Ethiopian and Oriental to China and Malaya.|
|8. Viverricula||Oriental only.|
|9. Paradoxurus||Oriental only.|
|10. Herpestes||Ethiopian, S. Palæarctic, and Oriental to Malaya.|
|11. Calogale||Ethiopian, Oriental to Cambodja.|
|13. Hyæna||Palæarctic and Ethiopian (a Palæarctic species.)|
|14. Canis||Palæarctic and Oriental to Malaya.|
|15. Cuon||Oriental to Malaya.|
|16. Vulpes||Very wide range.|
|17. Lutra||Oriental and Palæarctic.|
|19. Melursus||Oriental only; family not Ethiopian.|
|20. Sus||Palæarctic and Oriental, not Ethiopian.|
|22. Cervus||Oriental and Palæarctic; family not Ethiopian.|
|23. Cervulus||Oriental; family not Ethiopian.|
|24. Bibos||Palæarctic and Oriental.|
|26. Gazella||Palæarctic and Ethiopian.|
|29. Elephas||Oriental species.|
|30. Mus||Cosmopolite nearly.|
|32. Meriones||Very wide range.|
|34. Sciurus||Almost Cosmopolite.|
|35. Pteromys||Palæarctic and Oriental to China and Malaya,|
|36. Hystrix||Wide range.|
|37. Lepus||Wide range.|
|38. Manis||Ethiopian and Oriental to Malaya,|
Out of the above 38 genera, 8 have so wide a distribution as to give no special geographical indications. Of the remaining 30, whose geographical position we have noted, 14 are Oriental only; 5 have as much right to be considered Oriental as Ethiopian, extending as they do over the greater part of the Oriental region; 2 (the hyæna and gazelle) show Palæarctic rather than Ethiopian affinity; 7 are Palæarctic and Oriental but not Ethiopian; and only 2 (Cynælurus and Mellivora) can be considered as especially Ethiopian. We must also give due weight to the fact that we have here Ursidæ and Cervidæ, two families entirely absent from the Ethiopian region, and we shall then be forced to conclude that the affinities of the Indian peninsula are not only clearly Oriental, but that the Ethiopian element is really present in a far less degree than the Palæarctic.
Birds.—The naturalists who have adopted the "Ethiopian theory" of the fauna of Hindostan, have always supported their views by an appeal to the class of birds; maintaining, that not only are almost all the characteristic Himalayan and Malayan genera absent, but that their place is to a great extent supplied by others which are characteristic of the Ethiopian region. After a careful examination of the subject, Mr. Elwes, in a paper read before the Zoological Society (June 1873) came to the conclusion, that this view was an erroneous one, founded on the fact that the birds of the plains are the more abundant and more open to observation; and that these are often of wide-spread types, and some few almost exclusively African. The facts he adduced do not, however, seem to have satisfied the objectors; and as the subject is an important one, I will here give lists of all the genera of Passeres, Picariæ, Psittaci, Columbæ, and Gallinæ, which inhabit the sub-region, leaving out those which only just enter within its boundaries from adjacent sub-regions. These are arranged under four heads:—1. Oriental genera; which are either wholly confined to, or strikingly prevalent in, the Oriental region beyond the limits of the Indian peninsula. 2. Genera of Wide Range; which are fully as much entitled to be considered Oriental or Palæarctic as Ethiopian, and cannot be held to prove any Ethiopian affinity. 3. Palæarctic genera; which are altogether or almost absent from the Ethiopian region. 4. Ethiopian genera; which are confined to, or very prevalent in, the Ethiopian region, whence they extend into the Indian peninsula but not over the whole Oriental region. The last are the only ones which can be fairly balanced against those of the first list, in order to determine the character of the fauna.
1. Oriental Genera in Central India.
Geocichla, Orthotomus, Prinia, Megalurus, Abrornis, Larvivora, Copsychus, Kittacincla, Pomatorhinus, Malacocercus, Chatarrhæa, Layardia, Garrulax, Trochalopteron, Pellorneum, Dumetia, Pyctoris, Alcippe, Myiophonus, Sitta, Dendrophila, Phyllornis, Iora, Hypsipetes, Pericrocotus, Graucalus, Volvocivora, Chibia, Chaptia, Irena, Erythrosterna, Hemipus, Hemichelidon, Niltava, Cyornis, Eumyias, Hypothymis, Myialestes, Tephrodornis, Dendrocitta, Arachnechthra, Nectarophila, Arachnothera, Dicæum, Piprisoma, Munia, Eulabes, Pastor, Acridotheres, Sturnia, Sturnopastor, Artamus, Nemoricola, Pitta, Yungipicus, Chrysocolaptes, Hemicercus, Gecinus, Mulleripicus, Brachypternus, Tiga, Micropternus, Megalæma, Xantholæma, Rhopodytes, Taccocoua, Surniculus, Hierococcyx, Eudynamis, Nyctiornis, Harpactes, Pelargopsis, Ceyx, Hydrocissa, Meniceros, Batrachostomus, Dendrochelidon, Collocalia, Palæornis, Treron, Carpophaga, Chalcophaps, Ortygornis, Perdix, Pavo, Gallus, Galloperdix;—87 genera; and one peculiar genus, Salpornis, whose affinities are Palæarctic or Oriental.
2. Genera of Wide Range occurring in Central India.
Turdus, Monticola, Drymœca, Cisticola, Acrocephalus, Phylloscopus, Pratincola, Parus, Pycnonotus, Criniger, Oriolus, Dicrurus, Tchitrea, Lanius, Corvus, Zosterops, Hirundo, Cotyle, Passer, Ploceus, Estrilda, Alauda, Calandrella, Mirafra, Ammomanes, Motacilla, Anthus, Picus, Yunx, Centropus, Cuculus, Chrysococcyx, Coccystes, Coracias, Eurystomus, Merops, Alcedo, Ceryle, Halcyon, Upupa, Caprimulgus, Cypselus, Chætura, Columba, Turtur, Pterocles, Coturnix, Turnix;—48 genera.
3. Palæarctic Genera occurring in Central India.
Hypolais, Sylvia, Curruca, Cyanecula, Calliope, Chelidon, Euspiza, Emberiza, Galerita, Calobates, Corydalla;—11 genera.
4. Ethiopian Genera occurring in Central India.
Thamnobia, Pyrrhulauda, Pterocles, Francolinus;—4 genera.
A consideration of the above lists shows us, that the Hindostan sub-region is by no means so poor in forms of bird-life as is generally supposed (and as I had myself anticipated, it would prove to be), possessing, as it does, 151 genera of land-birds, without counting the Accipitres. It must also set at rest the question of the zoological affinities of the district, since a preponderance of 88 genera, against 4, cannot be held to be insufficient, and cannot be materially altered by any corrections in details that may be proposed or substantiated. Even of these four, only the first two are exclusively Ethiopian, Pterocles and Francolinus both being Palæarctic also. It is a question, indeed, whether anywhere in the world an outlying sub-region can be found, exhibiting less zoological affinity for the adjacent regions; and we have here a striking illustration of the necessity of deciding all such cases, not by examples, which may be so chosen as to support any view, but by carefully weighing and contrasting the whole of the facts on which the solution of the problem admittedly depends. It will, perhaps, be said that a great many of the 88 genera above given are very scarce and very local; but this is certainly not the case with the majority of them; and even where it is so, that does not in any degree affect their value as indicating zoo-geographical affinities. It is the presence of a type in a region, not its abundance or scarcity, that is the important fact; and when we have to do, as we have here, with many groups whose habits and mode of life necessarily seclude them from observation, their supposed scarcity may not even be a fact.
Reptiles and Amphibia.—Reptiles entirely agree with Mammalia and Birds in the main features of their distribution. Out of 17 families of snakes inhabiting Hindostan, 16 range over the greater part of the entire region, and only two can be supposed to show any Ethiopian affinity. These are the Psammophidæ and Erycidæ, both desert-haunting groups, and almost as much South Palæarctic as African. The genus Tropidococcyx is peculiar to the sub-region, and Aspidura, Passerita and Cynophis to the peninsula and Ceylon; while a large number of the most characteristic genera, as Dipsas, Simotes, Bungarus, Naja, Trimeresurus, Lycodon and Python, are characteristically Oriental.
Of the six families of lizards all have a wide range. The genera Eumeces, Pentadactylus, Gecko, Eublepharis, and Draco, are characteristically or wholly Oriental; Ophiops and Uromastix are Palæarctic; while Chamæleon is the solitary case of decided Ethiopian affinity.
Of the Amphibia not a single family exhibits special Ethiopian affinities.
II. Sub-region of Ceylon and South-India.
The Island of Ceylon is characterised by such striking peculiarities in its animal productions, as to render necessary its separation from the peninsula of India as a sub-region; but it is found that most of these special features extend to the Neilgherries and the whole southern mountainous portion of India, and that the two must be united in any zoo-geographical province. The main features of this division are,—the appearance of numerous animals allied to forms only found again in the Himalayas or in the Malayan sub-region, the possession of several peculiar generic types, and an unusual number of peculiar species.
Mammalia.—Among Mammalia the most remarkable form is Loris, a genus of Lemurs altogether peculiar to the sub-region; several peculiar monkeys of the genus Presbytes; the Malayan genus Tupaia; and Platacanthomys, a peculiar genus of Muridæ.
Birds.—Among birds it has Ochromela, a peculiar genus of flycatchers; Phœnicophaës (Cuculidæ) and Drymocataphus (Timaliidæ), both Malayan forms; a species of Myiophonus whose nearest ally is in Java; Trochalopteron, Brachypteryx, Buceros and Loriculus, which are only found elsewhere in the Himalayas and Malayana. It also possesses about 80 peculiar species of birds, including a large jungle fowl, one owl and two hornbills.
Reptiles.—It is however by its Reptiles, even more than by its higher vertebrates, that this sub-region is clearly characterised. Among snakes it possesses an entire family, Uropeltidæ, consisting of 5 genera and 18 species altogether confined to it,—Rhinophis and Uropeltis in Ceylon, Silybura, Plecturus and Melanophidium in Southern India. Four other genera of snakes, Haplocercus, Cercaspis, Peltopelor, and Hypnale are also peculiar; Chersydrus is only found elsewhere in Malaya; while Aspidura, Passerita, and Cynophis, only extend to Hindostan; and species of Eryx, Echis, and Psammophis show an affinity with Ethiopian and Palæarctic forms. Among lizards several genera of Agamidæ are peculiar, such as Otocryptis, Lyriocephalus, Ceratophora, Cophotis, Salea, Sitana and Charasia. In the family Acontiadæ, Nessia is peculiar to Ceylon, while a species of the African genus Acontias shows an affinity for the Ethiopian region.
Amphibia.—The genera of Amphibians that occur here are generally of wide range, but Nannophrys, Haplobatrachus, and Cacopus are confined to the sub-region; while Megalophrys is Malayan, and the species found in Ceylon also inhabit Java.
Insects.—The insects of Ceylon also furnish some curious examples of its distinctness from Hindostan, and its affinity with Malaya. Among its butterflies we find Papilio jophon, closely allied to P. antiphus of Malaya. The remarkable genus Hestia, so characteristic of the Malay archipelago, only occurs elsewhere on the mountains of Ceylon; while its Cynthia and Parthenos are closely allied to, if not identical with, Malayan species. Among Coleoptera we have yet more striking examples. The highly characteristic Malayan genus Tricondyla is represented in Ceylon by no less than 10 species; and among Longicorns we find the genera Tetraommatus, Thranius, Cacia, Praonetha, Ropica, and Serixia, all exclusively Malayan or only just entering the Indo-Chinese peninsula, yet all represented in Ceylon, while not a single species occurs in any part of India or the Himalayas.
The Past History of Ceylon and South-India as indicated by its Fauna.—In our account of the Ethiopian region we have already had occasion to refer to an ancient connection between this sub-region and Madagascar, in order to explain the distribution of the Lemurine type, and some other curious affinities between the two countries. This view is supported by the geology of India, which shows us Ceylon and South India consisting mainly of granitic and old metamorphic rocks, while the greater part of the peninsula, forming our first sub-region, is of tertiary formation, with a few isolated patches of secondary rocks. It is evident therefore, that during much of the tertiary period, Ceylon and South India were bounded on the north by a considerable extent of sea, and probably formed part of an extensive southern continent or great island. The very numerous and remarkable cases of affinity with Malaya, require however some closer approximation to these islands, which probably occurred at a later period. When, still later, the great plains and table-lands of Hindostan were formed, and a permanent land communication effected with the rich and highly developed Himalo-Chinese fauna, a rapid immigration of new types took place, and many of the less specialised forms of mammalia and birds (particularly those of ancient Ethiopian type) became extinct. Among reptiles and insects the competition was less severe, or the older forms were too well adapted to local conditions to be expelled; so that it is among these groups alone that we find any considerable number, of what are probably the remains of the ancient fauna of a now submerged southern continent.
III. Himalayan or Indo-Chinese Sub-region.
This, which is probably the richest of all the sub-regions, and perhaps one of the richest of all tracts of equal extent on the face of the globe, is essentially a forest-covered, mountainous country, mostly within the tropics, but on its northern margin extending some degrees beyond it, and rising in a continuous mountain range till it meets and intercalates with the Manchurian sub-division of the Palæarctic region. The peculiar mammalia, birds and insects of this sub-region begin to appear at the very foot of the Himalayas, but Dr. Gunther has shown that many of the reptiles characteristic of the plains of India are found to a height of from 2,000 to 4,000 feet.
In Sikhim, which may be taken as a typical example of the Himalayan portion of the sub-region, it seems to extend to an altitude of little less than 10,000 feet, that being the limit of the characteristic Timaliidæ or babbling thrushes; while the equally characteristic Pycnonotidæ, or bulbuls, and Treronidæ, or thick-billed fruit-pigeons, do not, according to Mr. Blanford, reach quite so high. We may perhaps take 9,000 feet as a good approximation over a large part of the Himalayan range; but it is evidently not possible to define the line with any great precision. Westward, the sub-region extends in diminishing breadth, till it terminates in or near Cashmere, where the fauna of the plains of India almost meets that of the Palæarctic region, at a moderate elevation. Eastward, it reaches into East Thibet and North-west China, where Père David has found a large number of the peculiar types of the Eastern Himalayas. A fauna, in general features identical, extends over Burmah and Siam to South China; mingling with the Palæarctic fauna in the mountains south of the Yang-tse-kiang river, and with that of Indo-Malaya in Tenasserim, and to a lesser extent in Southern Siam and Cochin China.
Zoological Characteristics of the Himalayan Sub-region.—Taking this sub-region as a whole, we find it to be characterised by 3 genera of mammalia (without counting bats), and 44 genera of land-birds, which are altogether peculiar to it; and by 13 genera of mammalia and 36 of birds, which it possesses in common with the Malayan sub-region; and besides these it has almost all the genera before enumerated as "Oriental," and several others of wide range, more especially a number of Palæarctic genera which appear in the higher Himalayas. The names of the more characteristic genera are as follows:—
Peculiar Himalo-Chinese Genera.
Mammalia.—Urva, Arctonyx, Ælurus.
Birds.—Suya, Horites, Chæmarrhornis, Tarsiger, Oreicola, Acanthoptila, Grammatoptila, Trochalopteron, Actinodura, Sibia, Suthora, Paradoxornis, Chlenasicus, Tesia, Rimator, Ægithaliscus, Cephalopyrus, Liothrix, Siva, Minla, Proparus, Cutia, Yuhina, Ixulus, Myzornis, Erpornis, Hemixus, Chibia, Niltava, Anthipes, Chelidorhynx, Urocissa, Pachyglossa, Heterura, Hæmatospiza, Ampeliceps, Saroglossa, Psarisomus, Serilophus, Vivia, Hyopicus, Gecinulus, Aceros, Ceriornis.
Genera common to the Himalo-Chinese and Malayan Sub-regions.
Mammalia.—Hylobates, Nycticebus, Viverricula, Prionodon, Arctitis, Paguma, Arctogale, Cuon, Gymnopus, Aonyx, Helictis, Rhinoceros, Nemorhedus, Rhizomys.
Birds.—Oreocincla, Notodela, Janthocincla, Timalia, Stachyris, Mixornis, Trichastoma, Enicurus, Pnœpyga, Melanochlora, Allotrius, Microscelis, Iole, Analcipus, Cochoa, Bhringa, Xanthopygia, Hylocharis, Cissa, Temnurus, Crypsirhina, Chalcostetha, Anthreptes, Chalcoparia, Cymbirhynchus, Hydrornis, Sasia, Venilia, Indicator, Carcineutes, Lyncornis, Macropygia, Argusianus, Polyplectron, Euplocamus, Phodilus.
SCENE IN NEPAUL, WITH CHARACTERISTIC ANIMALS.
Plate VII. Scene in Nepal, with Characteristic Himalayan Animals.—Our illustration contains figures of two mammals and two birds, characteristic of the higher woody region of the Himalayas. The lower figure on the left is the Helictis nepalensis, confined to the Eastern Himalayas, and belonging to a genus of the weasel family which is exclusively Oriental. It is marked with white on a grey-brown ground. Above it is the remarkable Panda (Ælurus fulgens), a beautiful animal with a glossy fur of a reddish colour, darker feet, and a white somewhat cat-like face. It is distantly allied to the bears, and more nearly to the American racoons, yet with sufficient differences to constitute it a distinct family. The large bird on the tree, is the horned Tragopan (Ceriornis satyra), one of the fine Himalayan pheasants, magnificently spotted with red and white, and ornamented with fleshy erectile wattles and horns, of vivid blue and red colours. The bird in the foreground is the Ibidorhynchus struthersii, a rare and curious wader, allied to the curlews and sandpipers but having the bill and feet red. It frequents the river-beds in the higher Himalayas, but has also been found in Thibet.
Reptiles.—Very few genera of reptiles are peculiar to this sub-region, all the more important ranging into the Malay islands. Of snakes the following are the more characteristic genera:—Typhline, Cylindrophis, Xenopeltis, Calamaria, Xenelaphis, Hypsirhina, Fordonia, several small genera of Homalopsidæ (Herpeton and Hipistes being characteristic of Burmah and Siam), Psammodynastes, Gonyosoma, Chrysopelea, Tragops, Dipsas, Pareas, Python, Bungarus, Naja, Callophis, and Trimeresurus. Naja reaches 8,000 feet elevation in the Himalayas, Tropidonotus 9,000 feet, Ablabes 10,000 feet, and Simotes 15,000 feet.
Of lizards, Pseudopus has one species in the Khasya hills while the other inhabits South-east Europe; and there are two small genera of Agamidæ peculiar to the Himalayas, while Draco and Calotes have a wide range and Acanthosaura, Dilophyrus, Physignathus, and Liolepis are found chiefly in the Indo-Chinese peninsula. There are several genera of Scincidæ; and the extensive genus of wall-lizards, Gecko, ranges over the whole region.
Of Amphibia, the peculiar forms are not numerous. Ichthyophis a genus of Cæciliadæ, is peculiar to the Khasya Hills; Tylotritron (Salamandridæ) to Yunan in Western China, and perhaps belongs to the Palæarctic region.
Of the tail-less Batrachians, Glyphoglossus is found in Pegu; Xenophrys in the Eastern Himalayas; while Callula, Ixalus, Rhacophorus, Hylarana, Oxyglossus, and Phrynoglossus, are common to the Himalo-Chinese and Malayan sub-regions.
Of the lizards, Colotes, Barycephalus, and Hinulia,—and of the Batrachia, Bufo,—are found at above 11,000 feet elevation in the Himalayas.
Insects.—So little has been done in working out the insect faunas of the separate sub-regions, that they cannot be treated in detail, and the reader is referred to the chapter on the distribution of insects in the part of this work devoted to Geographical Zoology. A few particulars may, however, be given as to the butterflies, which have been more systematically collected in tropical countries than any other order of insects. The Himalayan butterflies, especially in the eastern portions of the range—in Assam and the Khasya Hills—are remarkably fine and very abundant; yet all the larger groups extend into the Malayan sub-region, many to Ceylon, and a considerable proportion even to Africa and Austro-Malaya. There are a large number of peculiar types, but most of them consist of few or single species. Such are Neope, Orenoma, and Rhaphicera, genera of Satyridæ; Enispe (Morphidæ); Hestina, Penthema, and Abrota (Nymphalidæ); Dodona (Erycinidæ); Ilerda (Lycænidæ); Calinaga, Teinopalpus, and Bhutanitis (Papilionidæ). Its more prominent features are, however, derived from what may be termed Malayan, or even Old World types, such as Euplœa, among Danaidæ; Amathusia, Clerome, and Thaumantis, among Morphidæ; Euripus, Diadema, Athyma, Limenitis, and Adolias, among Nymphalidæ; Zemeros and Taxila among Erycinidæ; Amblypodia, Miletus, Ilerda, and Myrina, among Lycænidæ; Thyca, Prioneris, Dercas, Iphias, and Thestias among Pieridæ; and Papilios of the "Amphrisius," "Coon", "Philoxenus," "Protenor," "Paris," and "Sarpedon" groups. In the Himalayas there is an unusual abundance of large and gorgeous species of the genus Papilio, and of large and showy Nymphalidæ, Morphidæ, and Danaidæ, which render it, in favoured localities, only second to South America for a display of this form of beauty and variety in insect life.
Among the other orders of insects in which the Himalayas are remarkably rich, we may mention large and brilliant Cetoniidæ, chiefly of the genus Rhomborhina; a magnificent Lamellicorn, Euchirus macleayii, allied to the gigantic long-armed beetle (E. longimanus) of Amboyna; superb moths of the families Agaristidæ and Sesiidæ; elegant and remarkable Fulgoridæ, and strange forms of the gigantic Phasmidæ; most of which appear to be of larger size or of more brilliant colours than their Malayan allies.
Islands of the Indo-Chinese Sub-region.—A few important islands belong to this sub-region, the Andamans, Formosa, and Hainan being the most interesting.
Andamans.—The only mammalia are a few rats and mice, a Paradoxurus, and a pig supposed to be a hybrid race,—all of which may have been introduced by man's agency. The birds of the Andaman Islands have been largely collected, no less than 155 species having been obtained; and of these 17, (all land-birds) are peculiar. The genera are all found on the continent, and are mostly characteristic of the Indo-Chinese fauna, to which most of the species belong. Reptiles are also tolerably abundant; about 20 species are known, the majority being found also on the continent, while a few are peculiar. There are also a few Batrachia, and some fresh-water fishes, closely resembling those of Burmah. The absence of such mammalia as monkeys and squirrels, which abound on the mainland, and which are easily carried over straits or narrow seas by floating trees, is sufficient proof that these islands have not recently formed part of the continent. The birds are mostly such as may have reached the islands while in their present geographical position; and the occurrence of reptiles and fresh-water fishes, said to be identical in species with those of Burmah, must be due to the facilities, which some of these animals undoubtedly possess, for passing over a considerable width of sea. We must conclude, therefore, that these islands do not owe their existing fauna to an actual union with the mainland; but it is probable that they may have been formerly more extensive, and have then been less distant from the continent than at the present time.
The Nicobar Islands, usually associated with the Andamans, are less known, but present somewhat similar phenomena. They are, however, more Malayan in their fauna, and seem properly to belong to the Indo-Malay sub-region.
Formosa.—This island has been carefully examined by Mr. Swinhoe, who found 144 species of birds, of which 34 are peculiar. There is one peculiar genus, but the rest are all Indo-Chinese, though some of the species are more allied to Malayan than to Chinese or Himalayan forms. About 30 species of mammalia were found in Formosa, of which 11 are peculiar species, the rest being either Chinese or Himalayan. The peculiar species belong to the genera Talpa, Helictis, Sciuropterus, Pteromys, Mus, Sus, Cervus, and Capricornis. A few lizards and snakes of continental species have also been found. These facts clearly indicate the former connection of Formosa with China and Malaya, a connection which is rendered the more probable by the shallow sea which still connects all these countries.
Hainan.—The island of Hainan, on the south coast of China, is not so well known in proportion, though Mr. Swinhoe collected 172 species of birds, of which 130 were land-birds. Of these about 20 were peculiar species; the remainder being either Chinese, Himalayan, or Indo-Malayan. Mr. Swinhoe also obtained 24 species of mammalia, all being Chinese, Himalayan, or Indo-Malayan species except a hare, which is peculiar. This assemblage of animals would imply that Hainan, as might be anticipated from its position, has been more recently separated from the continent than the more distant island of Formosa.
IV. Indo-Malaya, or the Malayan Sub-region.
This sub-region, which is almost wholly insular (including only the Malayan peninsula on the continent of Asia), is equal, if not superior, in the variety and beauty of its productions, to that which we have just been considering. Like Indo-China, it is a region of forests, but it is more exclusively tropical; and it is therefore deficient in many of those curious forms of the temperate zone of the Himalayas, which seem to have been developed from Palæarctic rather than from Oriental types. Here alone, in the Oriental region, are found the most typical equatorial forms of life—organisms adapted to a climate characterised by uniform but not excessive heat, abundant moisture, and no marked departure from the average meteorological state, throughout the year. These favourable conditions of life only occur in three widely separated districts of the globe—the Malay archipelago, Western Africa, and equatorial South America. Hence perhaps it is, that the tapir and the trogons of Malacca should so closely resemble those of South America; and that the great anthropoid apes and crested hornbills of Western Africa, should find their nearest allies in Borneo and Sumatra.
Although the islands which go to form this sub-region are often separated from each other by a considerable expanse of sea, yet their productions in general offer no greater differences than those of portions of the Indo-Chinese sub-region separated by an equal extent of dry land. The explanation is easy, however, when we find that the sea which separates them is a very shallow one, so shallow that an elevation of only 300 feet would unite Sumatra, Java, and Borneo into one great South-eastern prolongation of the Asiatic continent. As we know that our own country has been elevated and depressed to a greater amount than this, at least twice in recent geological times, we can have no difficulty in admitting similar changes of level in the Malay archipelago, where the subterranean forces which bring about such changes are still at work, as manifested by the great chain of active volcanoes in Sumatra and Java. Proofs of somewhat earlier changes of level are to be seen in the Tertiary coal formations of Borneo, which demonstrate a succession of elevations and subsidences, with as much certainty as if we had historical record of them.
It is not necessary to suppose, nor is it probable, that all these great islands were recently united to the continent, and that their separation took place by one general subsidence of the whole. It is more consonant with what we know of such matters, that the elevations and depressions were partial, varying in their points of action and often recurring; sometimes extending one part of an island, sometimes another; now joining an island to the main land, now bringing two islands into closer proximity. There is reason to believe that sometimes an intervening island has sunk or receded and allowed others which it before separated to effect a partial union independently of it. If we recognise the probability that such varied and often-renewed changes of level have occurred, we shall be better able to understand how certain anomalies of distribution in these islands may have been brought about. We will now endeavour to sketch the general features of the zoology of this interesting district, and then proceed to discuss some of the relations of the islands to each other.
Mammalia.—We have seen that the Indo-Chinese sub-region possesses 13 species of mammalia in common with the Indo-Malay sub-region, and 4 others peculiar to itself, besides one Ethiopian and several Oriental and Palæarctic forms of wide range. Of this latter class the Malay islands have comparatively few, but they possess no less than 14 peculiar genera, viz. Simia, Siamanga, Tarsius, Galeopithecus, Hylomys, Ptilocerus, Gymnura, Cynogale, Hemigalea, Arctogale, Barangia, Mydaus, Helarctos, and Tapirus. The islands also possess tigers, deer, wild pigs, wild cattle, elephants, the scaly ant-eater, and most of the usual Oriental genera; so that they are on the whole fully as rich as, if not richer than, any part of Asia; a fact very unusual in island faunas, and very suggestive of their really continental nature.
A FOREST IN BORNEO, WITH CHARACTERISTIC MAMMALIA.
Plate VIII. Scene in Borneo with Characteristic Malayan Quadrupeds.—The Malayan fauna is so rich and peculiar that we devote two plates to illustrate it. We have here a group of mammalia, such as might be seen together in the vast forests of Borneo. In the foreground we have the beautiful deer-like Chevrotain (Tragulus javanicus). These are delicate little animals whose body is not larger than a rabbit's, thence often called "mouse-deer." They were formerly classed with the "musk-deer," owing to their similar tusk-like upper canines; but their anatomy shows them to form quite a distinct family, having more resemblance to the camels. On the branch above is the curious feather-tailed Tree-Shrew (Ptilocerus lowii), a small insectivorous animal altogether peculiar to Borneo. Above this is the strange little Tarsier (Tarsius spectrum), one of the lemurs confined to the Malay islands, but so distinct from all others as to constitute a separate family. The other small animals are the Flying Lemurs (Galeopithecus volans) formerly classed with the lemurs, but now considered to belong to the Insectivora. They have a very large expansion of the skin connecting the fore and hind limbs and tail, and are able to take long flights from one tree to another, and even to rise over obstacles in their course by the elevatory power of the tail-membrane. They feed chiefly on leaves, and have a very soft and beautifully marbled fur.
In the distance is the Malayan tapir (Tapirus indicus), a representative of a group of animals now confined to the larger Malay islands and tropical America, but which once ranged over the greater part of temperate Europe.
Birds.—Owing to several of the families consisting of very obscure and closely allied species, which have never been critically examined and compared by a competent ornithologist, the number of birds inhabiting this sub-region is uncertain. From the best available materials there appear to be somewhat less than 650 species of land-birds actually known, or excluding the Philippine Islands somewhat less than 600. The larger part of these are peculiar species, but mostly allied to those of Indo-China; 36 of the genera, as already stated, being common to these two sub-regions. There are, however, no less than 46 genera which are peculiarly or wholly Indo Malayan and, in many cases, have no close affinity with other Oriental groups. These peculiar genera are as follows:—Timalia, Malacopteron, Macronus, Napothera, Turdinus, and Trichixos—genera of Timaliidæ; Eupetes, a most remarkable form, perhaps allied to Enicurus, and Cinclus; Rhabdornis (Certhiidæ) found only in the Philippines; Psaltria, a diminutive bird of doubtful affinities, provisionally classed among the tits (Paridæ); Setornis (Pycnonotidæ); Lalage (Campephagidæ) extending eastward to the Pacific Islands; Pycnosphrys, Philentoma (Muscicapidæ); Laniellus, a beautiful bird doubtfully classed with the shrikes (Laniidæ); Platylophus and Pityriasis, the latter a most anomalous form—perhaps a distinct family, at present classed with the jays, in Corvidæ; Prionochilus, a curious form classed with Dicæidæ; Erythrura (Ploceidæ), extending eastwards to the Fiji Islands; Gymnops, Calornis, (Sturnidæ); Eurylæmus, Corydon, and Calyptomena (Eurylæmidæ); Eucichla, the longest tailed and most elegantly marked of the Pittidæ; Reinwardtipicus and Miglyptes (Picidæ); Psilopogon and Calorhamphus, (Megalæmidæ); Rhinococcyx, Dasylophus, Lepidogrammus, Carpococcyx, Zanclostomus, Poliococcyx, Rhinortha, (Cuculidæ); Berenicornis, Caldo, Cranorrhinus, Penelopides, Rhinoplax, (Bucerotidæ); Psittinus, (Psittacidæ); Ptilopus, Phapitreron, (Columbidæ); Rollulus, (Treronidæ); Machærhamphus, (Falconidæ). Many of these genera are abundant and wide-spread, while some of the most characteristic Himalayan genera, such as Larvivora, Garrulax, Hypsipetes, Pomatorhinus, and Dendrocitta, are here represented by only a few species.
Among the groups that are characteristic of the Malayan sub-region, the Timaliidæ and Pycnonotidæ stand pre-eminent; the former represented chiefly by the genera Timalia, Malacopteron, Macronus, and Trichastoma, the latter by Criniger, Microscelis, and many forms of Pycnonotus. The Muscicapidæ, Dicruridæ, Campephagidæ, Ploceidæ, and Nectariniidæ are also well developed; as well as the Pittidæ, and the Eurylæmidæ, the limited number of species of the latter being compensated by a tolerable abundance of individuals. Among the Picariæ are many conspicuous groups; as, woodpeckers (Picidæ); barbets (Megalæmidæ); trogons (Trogonidæ); kingfishers (Alcedinidæ); and hornbills (Bucerotidæ); five families which are perhaps the most conspicuous in the whole fauna. Lastly come the pigeons (Columbidæ), and the pheasants (Phasianidæ), which are fairly represented by such fine genera as Treron, Ptilopus, Euplocamus, and Argusianus. A few forms whose affinities are Australian rather than Oriental, help to give a character to the ornithology, though none of them are numerous. The swallow-shrikes (Artamus); the wag-tail fly-catchers (Rhipidura); the green fruit-doves (Ptilopus); and the mound-makers (Megapodius), are the chief of these.
There are a few curious examples of remote geographical alliances that may be noted. First, we have a direct African connection in Machærhamphus, a genus of hawks, and Berenicornis, a genus of hornbills; the only close allies being, in the former case in South, and in the latter in West Africa. Then we have a curious Neotropical affinity, indicated by Carpococcyx, a large Bornean ground-cuckoo, whose nearest ally is the genus Neomorphus of South America; and by the lovely green-coloured Calyptomena which seems unmistakably allied to the orange-coloured Rupicola, or "Cock of the rock," in general structure and in the remarkable form of crest, a resemblance which has been noticed by many writers.
In the preceding enumeration of Malayan genera several are included which extend into the Austro-Malay Islands, our object, at present, being to show the differences and relations of the two chief Oriental sub-regions.
Plate IX. A Malayan Forest with some of its peculiar Birds.—Our second illustration of the Malayan fauna is devoted to its bird-life; and for this purpose we place our scene in the Malay peninsula, where birds are perhaps more abundant and more interesting, than in any other part of the sub-region. Conspicuous in the foreground is the huge Rhinoceros Hornbill (Buceros rhinoceros), one of the most characteristic birds of the Malayan forests, the flapping of whose wings, as it violently beats the air to support its heavy body, may be heard a mile off. On the ground behind, is the Argus pheasant (Argusianus giganteus) whose beautifully ocellated wings have been the subject of a most interesting description in Mr. Darwin's Descent of Man. The wing-feathers are here so enormously developed for display (as shown in our figure) that they become almost, if not quite, useless for their original purpose of flight; yet the colours are so sober, harmonizing completely with the surrounding vegetation, and the bird is so wary, that in the forests where it abounds an old hunter assured me he had never been able to see a specimen till it was caught in his snares. It is interesting to note, that during the display of the plumage the bird's head is concealed by the wings from a spectator in front, and, contrary to what usually obtains among pheasants, the head is entirely unadorned, having neither crest nor a particle of vivid colour,—a remarkable confirmation of Mr. Darwin's views, that gayly coloured plumes are developed in the male bird for the purpose of attractive display in the breeding season. The long-tailed bird on the right is one of the Drongo-shrikes (Bhringa remifer), whose long bare tail-feathers, with an oar-like web at the end, and blue-black glossy plumage, render it a very attractive object as it flies after its insect prey. On the left is another singular bird the great Broad-bill (Corydon sumatranus), with dull and sombre plumage, but with a beak more like that of a boat-bill than of a fruit-eating passerine bird. Over all, the white-handed Gibbon (Hylobates lar) swings and gambols among the topmost branches of the forest.
Reptiles and Amphibia.—These are not sufficiently known to be of much use for our present purpose. Most of the genera belong to the continental parts of the Oriental region, or have a wide range. Of snakes Rhabdosoma, Typhlocalamus, Tetragonosoma, Acrochordus, and Atropos, are the most peculiar, and there are several peculiar genera of Homalopsidæ. Of Oriental genera, Cylindrophis, Xenopeltis, Calamaria, Hypsirhina, Psammodynastes, Gonyosoma, Tragops, Dipsas, Pareas, Python, Bungarus, Naja, and Callophis are abundant; as well as Simotes, Ablabes, Tropidonotus, and Dendrophis, which are widely distributed. Among lizards Hydrosaurus and Gecko are common; there are many isolated groups of Scincidæ; while Draco, Calotes, and many forms of Agamidæ, some of which are peculiar, abound.
A MALAYAN FOREST, WITH ITS CHARACTERISTIC BIRDS.
Among the Amphibia, toads and frogs of the genera Micrhyla, Kalophrynus, Ansonia, and Pseudobufo, are peculiar: while the Oriental Megalophrys, Ixalus, Rhacophorus, and Hylarana are abundant and characteristic.
Fishes.—The fresh-water fishes of the Malay archipelago have been so well collected and examined by the Dutch naturalists, that they offer valuable indications of zoo-geographical affinity; and they particularly well exhibit the sharply defined limits of the region, a large number of Oriental and even Ethiopian genera extending eastward as far as Java and Borneo, but very rarely indeed sending a single species further east, to Celebes or the Moluccas. Thirteen families of fresh-water fishes are found in the Indo-Malay sub-region. Of these the Sciænidæ and Symbranchidæ have mostly a wide range in the tropics. Ophiocephalidæ are exclusively Oriental, reaching Borneo and the Philippine islands. The Mastacembelidæ are also Oriental, but one species is found as far as Ceram. Of the Nandidæ, 3 genera range over the whole region. The Labyrinthici extend from Africa through the Oriental region to Amboyna, The single species constituting the family Luciocephalidæ is confined to Borneo and the small islands of Biliton and Banca. Of the extensive family Siluridæ 17 genera are Oriental and Malayan, and 11 are Malayan exclusively; and not one of these appears to pass beyond the limits of the sub-region. The Cyprinidæ offer an equally striking example, 23 genera ranging eastward to Java and Borneo and not one beyond; 14 of these being exclusively Malayan. It must be remembered that this is not from any want of knowledge of the countries farther east, as extensive collections have also been made in Celebes, the Moluccas, and Timor; so that the facts of distribution of fresh-water fishes come, most unexpectedly, to fortify that division of the archipelago into two primary regions, which was founded on a consideration of mammalia and birds only.
Insects.—Few countries in the world can present a richer and more varied series of insects than the Indo-Malay islands, and we can only here notice a few of their more striking peculiarities and more salient features.
The butterflies of this sub-region, according to the best estimate that can be formed, amount to about 650 described species, a number that will yet, no doubt, be very considerably increased. The genera which appear to be peculiar to it are Erites (Satyridæ); Zeuxidia (Morphidæ); Amnosia, Xanthotænia, and Tanæcia (Nymphalidæ). The groups which are most characteristic of the region, either from their abundance in individuals or species, or from their size and beauty, are—the rich dark-coloured Euplœa; the large semi-transparent Hestia; the plain-coloured Mycalesis, which replace our meadow-brown butterflies (Hipparchia); the curious Elymnias, which often closely resemble Euplœas; the large and handsome Thamantis and Zeuxidia, which take the place of the giant Morphos of South America; the Cethosia, of the brightest red, and marked with a curious zigzag pattern; the velvety and blue-glossed Terinos; the pale and delicately-streaked Cyrestis; the thick-bodied and boldly coloured Adolias; the small wine-coloured Taxila; the fine blue Amblypodia; the beautiful Thyca, elegantly marked underneath with red and yellow, which represent our common white butterflies and are almost equally abundant; the pale blue Eronia, and the large red-tipped Iphias. The genus Papilio is represented by a variety of fine groups; the large Ornithoptera, with satiny yellow under-wings; the superb green-marked "brookeana;" the "paradoxa" group, often closely resembling the Euplœas that abound in the same district; the "paris" group richly dusted with golden-green specks; the "helenus" group with wide-spreading black and white wings; the black and crimson "polydorus" group; the "memnon" group, of the largest size and richly-varied colours; and the "eurypilus" group, elegantly banded or spotted with blue or green: all these are so abundant that some of them are met with in every walk, and are a constant delight to the naturalist who has the privilege of observing them in their native haunts.
The Coleoptera are far less prominent and require to be carefully sought after; but they then well repay the collector. As affording some measure of the productiveness of the tropics in insect life it will not be out of place to give a few notes of the number of species collected by myself in some of the best localities. At Singapore 300 species of Coleoptera were collected in 15 days, and in a month the number had increased to 520; of which 100 were Longicorns and 140 Rhynchophora. At Sarawak in Borneo I obtained 400 species in 15 days, and 600 in a month. In two months this number had increased to about 850, and in three months to 1,000 species. This was the most prolific spot I ever collected in, especially for Longicorns which formed about one-fifth of all the species of beetles. In the Aru Islands in one month, I obtained only 235 species of Coleoptera, and about 600 species of insects of all orders; and this may be taken as a fair average, in localities where no specially favourable conditions existed. On the average 40 to 60 species of Coleoptera would be a good day's collecting; 70 exceptionally good; while the largest number ever obtained in one day was 95, and the majority of these would be very minute insects. It must be remembered, however, that many very common species were passed over, yet had every species met with been collected, not much more than 100 species would ever have been obtained in one day's collecting of four or five hours. These details may afford an interesting standard of comparison for collectors in other parts of the world.
Of Cicindelidæ the most peculiarly Malayan form is Therates, found always on leaves in the forests in the same localities as the more widely spread Collyris. Five genera of this family are Indo-Malayan.
The Carabidæ, though sufficiently plentiful, are mostly of small size, and not conspicuous in any way. But there is one striking exception in the purely Malayan genus Mormolyce, the largest and most remarkable of the whole family. It is nocturnal, resting during the days on the under side of large boleti in the virgin forest. Pericallus and Catascopus are among the few genera which are at all brillantly coloured.
Buprestidæ are abundant, and very gay; the genus Belionota being perhaps one of the most conspicuous and characteristic. The giant Catoxantha is, however, the most peculiar, though comparatively scarce. Chrysochroa and Chalcophora are also abundant and characteristic. Out of the 41 Oriental genera 21 are Malayan, and 10 of these are not found in the other sub-regions.
In Lucanidæ the Malay islands are rich, 14 out of the 16 Oriental genera occurring there, and 3 being peculiar. There are many fine species of Odontolabris, which may be considered the characteristic genus of the sub-region.
The Cetoniidæ are well represented by 16 genera and about 120 species. The genera Mycteristes, Phædimus, Plectrone, Euremina, Rhagopteryx and Centrognathus are peculiar, while Agestrata, Chalcothea, and Macronota are abundant and characteristic.
The Longicorns, as in all continental forest regions near the equator, are very abundant and in endlessly varied forms. No less than 55 genera containing about 200 species are peculiar to this sub-region, the Cerambycidæ being much the most numerous. Euryarthrum, Cœlosterna, Agelasta, and Astathes may be considered as most characteristic; but to name the curious and interesting forms would be to give a list of half the genera. For the relations of the Longicorns of the Indo-Malay, and those of the Austro-Malay region, the reader is referred to the chapter on the distribution of insects in the succeeding part of this work.
Terrestrial Mollusca.—The Philippine islands are celebrated as being one of the richest parts of the world for land shells, about 400 species being known. The other islands of the sub-region are far less rich, not more than about 100 species having yet been described from the whole of them. Helix and Bulimus both abound in species in the Philippines, whereas the latter genus is very scarce in Borneo and Java. Ten genera of Helicidæ inhabit the sub-region; Pfeifferia is found in the Philippines and Moluccas, while the large genus Cochlostyla is almost peculiar to the Philippines. Of the Operculata there are representatives of 20 genera, of which Dermatoma and Pupinella are peculiar, while Registoma and Callia extend to the Australian region. Cyclophorus, Leptopoma, and Pupina are perhaps the most characteristic genera.
The Zoological Relations of the Several Islands of the Indo-Malay Sub-region.
Although we have grouped the Philippine islands with the Indo-Malay sub-region, to which, as we shall see, they undoubtedly belong, yet most of the zoological characteristics we have just sketched out, apply more especially to the other groups of islands and the Malay peninsula. The Philippine islands stand, to Malaya proper, in the same relation that Madagascar does to Africa or the Antilles to South America; that is, they are remarkable for the absence of whole families and genera which everywhere characterise the remainder of the district. They are, in fact, truly insular, while the other islands are really continental in all the essential features of their natural history. Before, therefore, we can conveniently compare the separate islands of Malaya with each other, we must first deal with the Philippine group, showing in what its speciality consists, and why it must be considered apart from the sub-region to which it belongs.
Mammals of the Philippine Islands.—The only mammalia recorded as inhabiting the Philippine Islands are the following:—
|Quadrumana.||1. Macacus cynomolgus.|
|2. Cynopithecus niger.||Dr. Semper doubts this being a Philippine species.|
|Lemuroidea.||3. Tarsius spectrum.|
|Insectivora.||4. Galeopithecus philippinensis.|
|5. Tupaia (species).||On Dr. Semper's authority.|
|Carnivora.||6. Viverra tangalunga.|
|7. Paradoxurus philippensis.|
|Ungulata.||8. Sus (species).||On Dr. Semper's authority.|
|9. Cervus mariannus.|
|10. Cervus philippensis.|
|11. Cervus alfredi.|
|12. Bos (species).||Wild cattle; perhaps introduced.|
|Rodentia.||13. Phlæomys cummingii.|
|14. Sciurus philippinensis.|
|Also 24 species, belonging to 17 genera, of bats.|
The foregoing list, although small, contains an assemblage of species which are wholly Oriental in character, and several of which (Tarsius, Galeopithecus, Tupaia) are characteristic and highly peculiar Malayan forms. At the same time these islands are completely separated from the rest of Malaya by the total absence of Semnopithecus, Hylobates, Felis, Helarctos, Rhinoceros, Manis, and other groups constantly found in the great Indo-Malay islands and peninsula of Malacca. We find apparently two sets of animals: a more ancient series, represented by the deer, Galeopithecus, and squirrel, in which the species are distinct from any others; and a more recent series, represented by Macacus cynomolgus, and Viverra tangalunga, identical with common Malayan animals. The former indicate the earliest period when these volcanic islands were connected with some part of the Malayan sub-region, and they show that this was not geologically remote, since no peculiar generic types have been preserved or differentiated. The latter may indicate either the termination of the period of union, or merely the effects of introduction by man. The reason why a larger number of mammalian forms were not introduced and established, was probably because the union was effected only with some small islands, and from these communicated to other parts of the archipelago; or it may well be that later subsidences extinguished some of the forms that had established themselves.
Birds of the Philippine Islands.—These have been carefully investigated by Viscount Walden, in a paper read before the Zoological Society of London in 1873, and we are thus furnished with ample information on the relations of this important portion of the fauna.
The total number of birds known to inhabit the Philippines is 219, of which 106 are peculiar. If, however, following our usual plan, we take only the land-birds, we find the numbers to be 159 species, of which 100 are peculiar; an unusually large proportion for a group of islands so comparatively near to various parts of the Oriental and Australian regions. The families of birds which are more especially characteristic of the Indo-Malay sub-region are about 28 in number, and examples of all these are found in the Philippines except four, viz., Cinclidæ, Phyllornithidæ, Eurylæmidæ, and Podargidæ. The only Philippine families which are, otherwise, exclusively Austro-Malayan are, Cacatuidæ and Megapodiidæ. Yet although the birds are unmistakably Malayan, as a whole, there are, as in the mammalia (though in a less degree), marked deficiencies of most characteristic Malayan forms. Lord Walden gives a list of no less than 69 genera thus absent; but it will be sufficient here to mention such wide-spread and specially Indo-Malay groups as,—Eurylæmus, Nyctiornis, Arachnothera, Geocichla, Malacopteron, Timalia, Pomatorhinus, Phyllornis, Iora, Criniger, Enicurus, Chaptia, Tchitrea, Dendrocitta, Eulabes, Palæornis, Miglyptes, Tiga, and Euplocamus. These deficiencies plainly show the isolated character of the Philippine group, and imply that it has never formed a part of that Indo-Malayan extension of the continent which almost certainly existed when the peculiar Malayan fauna was developed; or that, if it has been so united, it has been subsequently submerged and broken up to such an extent, as to cause the extinction of many of the absent types.
It appears from Lord Walden's careful analysis, that 31 of the Philippine species occur in the Papuan sub-region, and 47 in Celebes; 69 occur also in India, and 75 in Java. This last fact is curious, since Java is the most remote of the Malayan islands, but it is found to arise almost wholly from the birds of that island being better known, since only one species, Xantholæma rosea, is confined to the Philippine Islands and Java.
The wading and swimming birds are mostly of wide-spread forms, only 6 out of the 60 species being peculiar to the Philippine archipelago. Confining ourselves to the land-birds, and combining several of the minutely subdivided genera of Lord Walden's paper so as to agree with the arrangement adopted in this work, we find that there are 112 genera of land-birds represented in the islands. Of these, 50 are either cosmopolitan, of wide range, or common to the Oriental and Australian regions, and may be put aside as affording few indications of geographical affinity. Of the remaining 62 no less than 40 are exclusively or mainly Oriental, and most of them are genera which range widely over the region, only two (Philentoma and Rollulus) being exclusively Malayan, and two others (Megalurus and Malacocircus) more especially Indian or continental. Five other genera, though having a wide range, are typically Palæarctic, and have reached the islands through North China. They are, Monticola, Acrocephalus, Phylloscopus, Calliope, and Passer; the two first having extended their range southward into the Moluccas. The peculiarly Australian genera are only 12, the majority being characteristic Papuan and Moluccan forms; such as—Campephaga, Alcyone, Cacatua, Tanygnathus, Ptilopus, Ianthœnas, <Phlogœnas, and Megapodius. One is peculiar to Celebes (Prioniturus); one to the Papuan group (Cyclopsitta); and one is chiefly Australian (Gerygone). The beautiful little parroquets forming the genus Loriculus, are characteristic of the Philippines, which possess 5 species, a larger number than occurs in any other group of islands, though they range from India to New Guinea. There remain six peculiar genera—Rhabdornis, an isolated form of creepers (Certhiidæ); Gymnops, a remarkable bareheaded bird belonging to the starlings (Sturnidæ); Dasylophus, and Lepidogrammus, remarkable genera of cuckoos (Cuculidæ); Penelopides, a peculiar hornbill, and Phapitreron, a genus of pigeons. Besides these there are four other types (here classed as sub-genera, but considered to be distinct by Lord Walden) which are peculiar to the Philippines. These are Pseudoptynx, an owl of the genus Athene; Pseudolalage, a sub-genus of Lalage; Zeocephus, a sub-genus of Tchitrea; and Ptilocolpa, included under Carpophaga.
When we look at the position of the Philippine group, connected by the Bashee islands with Formosa, by Palawan and the Sooloo archipelago with Borneo, and by the Tulour and other islets with the Moluccas and Celebes, we have little difficulty in accounting for the peculiarities of its bird fauna. The absence of a large number of Malayan groups would indicate that the actual connection with Borneo, which seems necessary for the introduction of the Malay types of mammalia, was not of long duration; while the large proportion of wide-spread continental genera of birds would seem to imply that greater facilities had once existed for immigration from Southern China, perhaps by a land connection through Formosa, at which time the ancestors of the peculiar forms of deer entered the country. It may indeed be objected that our knowledge of these islands is far too imperfect to arrive at any satisfactory conclusions as to their former history; but although many more species no doubt remain to be discovered, experience shows that the broad characters of a fauna are always determined by a series of collections made by different persons, at various localities, and at different times, even when more imperfect than those of the Philippine birds really are. The isolated position, and the volcanic structure of the group, would lead us to expect them to be somewhat less productive than the Moluccas, close to the rich and varied Papuan district,—or than Celebes, with its numerous indications of an extensive area and great antiquity; and taking into account the excessive poverty of its mammalian fauna, which is certain to be pretty well known, I am inclined to believe that no future discoveries will materially alter the character of Philippine ornithology, as determined from the materials already at our command.
Java.—Following the same plan as we have adopted in first discussing the Philippine islands, and separating them from the body of the sub-region on account of special peculiarities, we must next take Java, as possessing marked individuality, and as being to some extent more isolated in its productions than the remaining great islands.
Java is well supplied with indigenous mammalia, possessing as nearly as can be ascertained 55 genera and 90 species. None of these genera are peculiar, and only about 5 of the species,—3 quadrumana, a deer and a wild pig. So far then there is nothing remarkable in its fauna, but on comparing it with that of the other great islands, viz., Borneo and Sumatra, and the Malay peninsula, we find an unmistakable deficiency of characteristic forms, the same in kind as that we have just commented on in the case of the Philippines, though much less in degree. First, taking genera which are found in all three of the above-named localities and which must therefore be held to be typical Malayan groups, the following are absent from Java: Viverra, Gymnopus, Lutra, Helarctos, Tapirus, Elephas, and Gymnura; while of those known to occur in two, and which, owing to our imperfect knowledge, may very probably one day be discovered in the third, the following are equally wanting: Simia, Siamanga, Hemigalea, Paguma, Rhinosciurus, and Rhizomys. It may be said this is only negative evidence, but in the case of Java it is much more, because this island is not only the best known of any in the archipelago, but there is perhaps no portion of British India of equal extent so well known. It is one of the oldest of the Dutch possessions and the seat of their colonial government; good roads traverse it in every direction, and experienced naturalists have been resident in various parts of it for years together, and have visited every mountain and every forest, aided by bands of diligent native collectors. We should be almost as likely to find new species of mammalia in Central Europe as in Java; and therefore the absence of such animals as the Malay bear, the elephant, tapir, gymnura, and even less conspicuous forms, must be accepted as a positive fact.
In the other islands there are still vast tracts of forest in the hands of natives and utterly unexplored, and any similar absence in their case will prove little; yet on making the same comparison in the case of Borneo, the most peculiar and the least known of the other portions of the sub-region, we find only 2 genera absent which are found in the three other divisions, and only 3 which are found in two others. A fact to be noted also is, that the only genus found in Java but not in other parts of the sub-region (Helictis) occurs again in North India; and that some Javan species, as Rhinoceros javanicus, and Lepus kurgosa occur again in the Indo-Chinese sub-region, but not in the Malayan.
Among the birds we meet with facts of a similar import; and though the absence of certain types from Java is not quite so certain as among the mammalia, this is more than balanced by the increased number of such deficiencies, so that if a few should be proved to be erroneous, the main result will remain unaltered.
Java possesses about 270 species of land birds, of which about 40 are peculiar to it. There are, however, very few peculiar genera, Laniellus, a beautiful spotted shrike, being the most distinct, while Cochoa and Psaltria are perhaps not different from their Indian allies. The island has however a marked individuality in two ways—in the absence of characteristic Malayan types, and in the presence of a number of forms not yet found in any of the other Malay islands, but having their nearest allies in various parts of the Indo-Chinese sub-region. The following 16 genera are all found in Malacca, Sumatra, and Borneo, but are absent from Java: Setornis, Temnurus, Dendrocitta, Corydon, Calyptomena, Venilia, Reinwardtipicus, Caloramphus, Rhinortha, Nyctiornis, Cranorrhinus, Psittinus, Polyplectron, Argusianus, Euplocamus, and Rollulus. The following 9 are known from two of the above localities, and will very probably be found in the third, but are absent from, and not likely to occur in, Java: Trichixos, Eupetes, Melanochlora, Chaptia, Pityriasis, Lyncornis, Carpococcyx, Poliococcyx, and Rhinoplax. We have thus 25 typically Malayan genera which are not known to occur in Java.
The following genera, on the other hand, do not occur in any of the Malayan sub-divisions except Java, and they all occur again, or under closely allied forms, in the Indo-Chinese sub-region; Brachypteryx (allied species in Himalayas); Zoothera (allied species in Aracan); Notodela (allied species in Pegu); Pnoëpyga (allied species in Himalayas); Allotrius (allied species in the Himalayas); Cochoa (allied species in the Himalayas); Crypsirhina (allied species in Burmah); Estrilda (allied species in India); Psaltria (allied genus—Ægithaliscus—in Himalayas); Pavo muticus and Harpactes oreskios (same species in Siam and Burmah); Cecropis striolata (same species in Java and Formosa, and allied species in India).
Here we have 12 instances of very remarkable distribution, and considering that there are nearly as many birds known from Sumatra and Borneo as from Java, and considerably more from the Malay peninsula, it is not likely that many of these well marked forms will be discovered in these countries.
There are also a considerable number of species of birds common to Malacca, Sumatra, and Borneo, but represented in Java by distinct though closely allied species. Such are,—
|Venilia malaccensis||(represented in||Java by)||V. miniata.|
|Drymocataphus nigrocapitatus||"||"||D. capistratus.|
|Malacopteron coronatum||"||"||M. rufifrons.|
|Irena cyanea||"||"||I. turcosa.|
|Ploceus baya||"||"||P. hypoxantha.|
|Loriculus galgulus||"||"||L. pusillus.|
|Ptilopus jambu||"||"||P. porphyreus.|
Now if we look at our map of the region, and consider the position of Java with regard to Borneo, Sumatra, and the Indo-Chinese peninsula, the facts just pointed out appear most anomalous and perplexing. First, we have Java and Sumatra forming one continuous line of volcanoes, separated by a very narrow strait, and with all the appearance of having formed one continuous land; yet their productions differ considerably, and those of Sumatra show the closest resemblance to those of Borneo, an island ten times further off than Java and differing widely in the absence of volcanoes or any continuous range of lofty mountains. Then again, not only does Java differ from these two, but it agrees with a country beyond them both—a country from which they seem to have a much better chance to have been supplied by immigration than Java has, and to have (almost necessarily) participated, even more largely, in the benefits of any means of transmission capable of reaching the latter island. Yet more; whatever changes have occurred to bring about the anomalous state of things that exists must have been, zoologically and geologically, recent; for the strange cross-affinities between Java and the Indo-Chinese continent (in which Sumatra and Borneo have not participated), as well as that between Malacca, Sumatra, and Borneo (in which Java has not participated) are exhibited, in many cases by community of species, in others by the presence of very closely allied forms of the same genera, of mammalia and birds. Now we know that these higher animals become replaced by allied species much more rapidly than the mollusca; and it is also pretty certain that the modification by which this replacement is effected takes place more rapidly when the two sets of individuals are isolated from each other, and especially when they are restricted to islands, where they are necessarily subject to distinct and pretty constant conditions, both physical and organic. It becomes therefore almost a certainty, that Siam and Java on the one hand, and Sumatra, Borneo, and Malacca on the other must have been brought into some close connexion, not earlier than the newer Pliocene period; but while the one set of countries were having their meeting, the other must have been by some means got out of the way. Before attempting to indicate the mode by which this might have been effected in accordance with what we know of the physical geography, geology, and vegetation of the several islands, it will be as well to complete our sketch of their zoological relations to each other, so as ascertain with some precision, what are the facts of distribution which we have to explain.
Malacca, Sumatra, and Borneo.—After having set apart the Philippine Islands and Java, we have remaining two great islands and a peninsula, which, though separated by considerable arms of the sea, possess a fauna of wonderful uniformity having all the typical Malayan features in their full development. Their unity is indeed so complete, that we can find hardly any groups of sufficient importance by which to differentiate them from each other; and we feel no confidence that future discoveries may not take away what speciality they possess. One after another, species or genera once peculiar to Borneo or Sumatra have been found elsewhere; and this has gone to such an extent in birds, that hardly a peculiar genus and very few peculiar species are left in either island. Borneo however is undoubtedly the most peculiar. It possesses three genera of Mammalia not found elsewhere; Cynogale, a curious carnivore allied to the otters; with Dendrogale and Ptilocerus, small insectivora allied to Tupaia. It has Simia, the Orang-utan, and Paguma, one of the Viverridæ, in common with Sumatra; as well as Rhinosciurus, a peculiar form of squirrel, and Hemigalea, one of the Viverridæ, in common with Malacca. Sumatra has only one genus not found in any other Malayan district—Nemorhedus, a form of antelope which occurs again in North India. It also has Siamanga in common with Malacca, Mydaus with Java, and Rhizomys with India. The Malay Peninsula seems to have no peculiar forms of Mammalia, though it is rich in all the characteristic Malay types.
The bats of the various islands have been very unequally collected, 36 species being recorded from Java, 23 from Sumatra, but only 16 each from Borneo and Malacca. Leaving these out of consideration, and taking into account the terrestrial mammals only, we find that Java is the poorest in species, while Borneo, Sumatra, and Malacca are tolerably equal; the numbers being 55, 62, 66, and 65 respectively. Of these we find that the species confined to each island or district are (in the same order) 6, 16, 5, and 6. It thus appears that Borneo is, in its mammalia, the most isolated and peculiar; next comes Sumatra, and then Malacca and Java, as shown by the following table.
This result differs from that which we have arrived at by the more detailed consideration of the fauna of Java; and it serves to show that the estimate of a country by the number of its peculiar genera and species alone, may not always represent its true zoological importance or its most marked features. Java, as we have seen, is differentiated from the other three districts by the absence of numerous types common to them all, and by its independent continental relations. Borneo is also well distinguished by its peculiar genera and specific types, yet it is at the same time more closely related to Sumatra and Malacca than is Java. The two islands have evidently had a very different history, which a detailed knowledge of their geology would alone enable us to trace. Should we ever arrive at a fair knowledge of the physical changes that have resulted in the present condition, we shall almost certainly find that many of the differences and anomalies of their existing fauna and flora will be accounted for.
In Birds we hardly find anything to differentiate Borneo and Sumatra in any clear manner. Pityriasis and Carpococcyx, once thought peculiar to the former, are now found also in the latter; and we have not a single genus left to characterize Borneo except Schwaneria a peculiar fly-catcher, and Indicator, an African and Indian group not known to occur elsewhere in the Malay sub-region. Sumatra as yet alone possesses Psilopogon, a remarkable form of barbet, but we may well expect that it will be soon found in the interior of Borneo or Malacca; it also has Berenicornis, an African form of hornbill. The Malay Peninsula appears to have no genus peculiar to it, but it possesses some Chinese and Indian forms which do not pass into the islands. As to the species, our knowledge of them is at present very imperfect. The Malay Peninsula is perhaps the best known, but it is probable that both Sumatra and Borneo are quite as rich in species. With the exception of the genera noted above, and two or three others as yet found in two islands only, the three districts we are now considering may be said to have an almost identical bird-fauna, consisting largely of the same species and almost wholly of these together with closely allied species of the same genera. There are no well-marked groups which especially characterise one of these islands rather than the other, so that even the amount of speciality which Borneo undoubtedly exhibits as regards mammalia, is only faintly shown by its birds. The Pittidæ may perhaps be named as the most characteristic Bornean group, that island possessing six species, three of which are peculiar to it and are among the most beautiful birds of an unusually beautiful family. Yet Sumatra possesses two peculiar, and hardly less remarkable species.
In other classes of vertebrates, in insects, and in land-shells, our knowledge is far too imperfect to allow of our making any useful comparison between the faunas.
Banca.—We must, however note the fact of peculiar species occurring in Banca, a small island close to Sumatra, and thus offering another problem in distribution. A squirrel (Sciurus bangkanus) is allied to three species found in Malacca, Sumatra, and Borneo respectively, but quite as distinct from them all as they are from each other. More curious are the two species of Pitta peculiar to Banca; one, Pitta megarhynchus, is allied to the P. brachyurus, which inhabits the whole sub-region and extends to Siam and China, but differs from it in its very large bill and differently coloured head; the other, P. bangkanus, is allied to P. cucullatus, which extends from Nepal to Malacca, and to P. sordidus, which inhabits both Borneo and Sumatra as well as the Philippines.
We have here, on a small scale, a somewhat similar problem to that of Java, and as this is comparatively easy of solution we will consider it first. Although, on the map, Banca is so very close to Sumatra, the observer on the spot at once sees that the proximity has been recently brought about. The whole south-east coast of Sumatra is a great alluvial plain, hardly yet raised above the sea level, and half flooded in the wet season. It is plainly a recent formation, caused by the washing down into a shallow sea of the débris from the grand range of volcanic mountains 150 miles distant. Banca, on the other hand is, though low, a rugged and hilly island, formed almost wholly of ancient rocks of apparently volcanic origin, and closely resembling parts of the Malay Peninsula and the intervening chain of small islands. There is every appearance that Banca once formed the extremity of the Peninsula, at which time it would probably have been separated from Sumatra by 50 or 100 miles of sea. Its productions should, therefore, most resemble those of Singapore and Malacca, and the few peculiar species it possesses will be due to their isolation in a small tract of country, surrounded by a limited number of animal and vegetable forms, and subject to the influence of a peculiar soil and climate. The parent species existing in such large tracts as Borneo or Sumatra, subjected to more varied conditions of soil, climate, vegetation, food, and enemies, would preserve, almost or quite unchanged, the characteristics which had been developed under nearly identical conditions when the great island formed part of the continent. Geology teaches us that similar changes in the forms of the higher vertebrates have taken place during the Post-Tertiary epoch; and there are other reasons for believing that, under such conditions of isolation as in Banca, the change may have required but a very moderate period, even reckoned in years. We will now return to the more difficult problem presented by the peculiar continental relations of Java, as already detailed.
Probable Recent Geographical Changes in the Indo-Malay Islands.—Although Borneo is by far the largest of the Indo-Malay islands, yet its physical conformation is such that, were a depression to occur of one or two thousand feet, it would be reduced to a smaller continuous area than either Sumatra or Java. Except in its northern portion it possesses no lofty mountains, while alluvial valleys of great extent penetrate far into its interior. A very moderate depression, of perhaps 500 feet, would convert it into an island shaped something like Celebes; and its mountains are of so small an average elevation, and consist so much of isolated hills and detached ranges, that a depression of 2,000 feet would almost certainly break it up into a group of small islands, with a somewhat larger one to the north. Sumatra (and to a less extent Java) consists of an almost continuous range of lofty mountains, connected by plateaus from 3,000 to 4,000 feet high; so that although a depression of 2,000 feet would greatly diminish their size, it would probably leave the former a single island, while the latter would be separated into two principal islands of still considerable extent. The enormous amount of volcanic action in these two islands, and the great number of conical mountains which must have been slowly raised, chiefly by ejected matter, to the height of 10,000 and 12,000 feet, and whose shape indicates that they have been formed above water, renders it almost certain that for long periods they have not undergone submersion to any considerable extent. In Borneo, however, we have no such evidences. No volcano, active or extinct, is known in its entire area; while extensive beds of coal of tertiary age, in every part of it, prove that it has been subject to repeated submersions, at no distant date geologically. An indication, if not a proof, of still more recent submersion is to be found in the great alluvial valleys which on the south and south-west extend fully 200 miles inland, while they are to a less degree a characteristic feature all round the island. These swampy plains have been formed by the combined action of rivers and tides; and they point clearly to an immediately preceding state of things, when that which is even now barely raised above the ocean, was more or less sunk below it.
These various indications enable us to claim, as an admissible and even probable supposition, that at some epoch during the Pliocene period of geology, Borneo, as we now know it, did not exist; but was represented by a mountainous island at its present northern extremity, with perhaps a few smaller islets to the south. We thus have a clear opening from Java to the Siamese Peninsula; and as the whole of that sea is less than 100 fathoms deep, there is no difficulty in supposing an elevation of land connecting the two together, quite independent of Borneo on the one hand and Sumatra on the other. This union did not probably last long; but it was sufficient to allow of the introduction into Java of the Rhinoceros javanicus, and that group of Indo-Chinese and Himalayan species of mammalia and birds which it alone possesses. When this ridge had disappeared by subsidence, the next elevation occurred a little more to the east, and produced the union of many islets which, aided by sub-aerial denudation, formed the present island of Borneo. It is probable that this elevation was sufficiently extensive to unite Borneo for a time with the Malay Peninsula and Sumatra, thus helping to produce that close resemblance of genera and even of species, which these countries exhibit, and obliterating much of their former speciality, of which, however, we have still some traces in the long-nosed monkey and Ptilocerus of Borneo, and the considerable number of genera both of mammalia and birds confined to two only out of the three divisions of typical Malaya. The subsidence which again divided these countries by arms of the sea rather wider than at present, might have left Banca isolated, as already referred to, with its proportion of the common fauna to be, in a few instances, subsequently modified.
Thus we are enabled to understand how the special relations of the species of these islands to each other may have been brought about. To account for their more deep-seated and general zoological features, we must go farther back.
Probable Origin of the Malayan Fauna.—The typical Malayan fauna is essentially an equatorial one, and must have been elaborated in an extensive equatorial area. This ancient land almost certainly extended northward over the shallow sea as far as the island of Palawan, the Paracels shoals and even Hainan. To the east, it may at one time have included the Philippines and Celebes, but not the Moluccas. To the south it was limited by the deep sea beyond Java. It included all Sumatra and the Nicobar islands, and there is every reason to believe that it stretched out also to the west so as to include the central peak of Ceylon, the Maldive isles, and the Cocos islands west of Sumatra. We should then have an area as extensive as South America to 15° south latitude, and well calculated to develop that luxuriant fauna and flora which has since spread to the Himalayas. The submergence of the western half of this area (leaving only a fragment in Ceylon) would greatly diminish the number of animals and perhaps extinguish some peculiar types; but the remaining portion would still form a compact and extensive district, twice as large as the peninsula of India, over the whole of which a uniform Malayan fauna would prevail. The first important change would be the separation of Celebes; and this was probably effected by a great subsidence, forming the deep strait that now divides that island from Borneo. During the process Celebes itself was no doubt greatly submerged, leaving only a few islands in which were preserved that remnant of the ancient Malayan fauna that now constitutes one of its most striking and anomalous features. The Philippine area would next be separated, and perhaps be almost wholly submerged; or broken up into many small volcanic islets in which a limited number of Malayan types alone survived. Such a condition of things will account for the very small variety of mammalia compared with the tolerably numerous genera of birds, that now characterise its fauna; while both here and in Celebes we find some of the old Malayan types preserved, which, in the extended area of the Sunda Isles have been replaced by more dominant forms.
The next important change would be the separation of Java; and here also no doubt a considerable submergence occurred, rendering the island an unsuitable habitation for the various Malay types whose absence forms one of its conspicuous features. It has since remained permanently separated from the other islands, and has no doubt developed some peculiar species, while it may have preserved some ancient forms which in the larger area have become changed. From the fact that a number of its species are confined either to the western or the eastern half of the island, it is probable that it long continued as two islands, which have become united at a comparatively recent period. It has also been subjected to the immigration of Indo-Chinese forms, as already referred to in the earlier part of this sketch.
We have thus shown how the main zoological features of the several sub-divisions of the Malayan sub-region may be accounted for, by means of a series of suppositions as to past changes which, though for the most part purely hypothetical, are always in accordance with what we know both of the physical geography and the zoology of the districts in question and those which surround them. It may also be remarked, that we know, with a degree of certainty which may be called absolute, that alternate elevation and subsidence is the normal state of things all over the globe; that it was the rule in the earliest geological epochs, and that it has continued down to the historical era. We know too, that the amount of elevation and subsidence that can be proved to have occurred again and again in the same area, is often much greater than is required for the changes here speculated on,—while the time required for such changes is certainly less than that necessitated by the changes of specific and generic forms which have coincided with, and been to a large extent dependent on them. We have, therefore, true causes at work, and our only suppositions have been as to how those causes could have brought about the results which we see; and however complex and unlikely some of the supposed changes may seem to the reader, the geologist who has made a study of such changes, as recorded in the crust of the earth, will not only admit them to be probable, but will be inclined to believe that they have really been far more complex and more unexpected than any supposition we can make about them.
There is one other external relation of the Malayan fauna about which it may be necessary to say a few words. I have supposed the greatest westward extension of the Malayan area to be indicated by the Maldive islands, but some naturalists would extend it to include Madagascar in order to account for the range of the Lemuridæ. Such an extension would, however, render it difficult to explain the very small amount of correspondence with a pervading diversity, between the Malayan and Malagasy faunas. It seems more reasonable to suppose an approximation of the two areas, without actual union having ever occurred. This approximation would have allowed the interchange of certain genera of birds, which are common to the Oriental Region and the Mascarene islands, but it would have been too recent to account for the diffusion of the lemurs, which belong to distinct genera and even distinct families. This probably dates back to a much earlier period, when the lemurine type had a wide range over the northern hemisphere. Subjected to the competition of higher forms, these imperfectly developed groups have mostly died out, except a few isolated examples, chiefly found in islands, and a few groups in Africa.
In our discussion of the origin of the Ethiopian fauna, we have supposed that a close connection once existed between Madagascar and Ceylon. This was during a very early tertiary epoch; and if, long after it had ceased and the fauna of Ceylon and South India had assumed somewhat more of their present character, we suppose the approximation or union of Ceylon and Malaya to have taken place, we shall perhaps be able to account for most of the special affinities they present, with the least amount of simultaneous elevation of the ocean bed; which it must always be remembered, requires a corresponding depression elsewhere to balance it.
Concluding Remarks on the Oriental Region.—We have already so fully discussed the internal and external relations of the several sub-regions, that little more need be said. The rich and varied fauna which inhabited Europe at the dawn of the tertiary period,—as shown by the abundant remains of mammalia wherever suitable deposits of Eocene age have been discovered,—proves, that an extensive Palæarctic continent then existed; and the character of the flora and fauna of the Eocene deposits is so completely tropical, that we may be sure there was then no barrier of climate between it and the Oriental region. At that early period the northern plains of Asia were probably under water, while the great Thibetan plateau and the Himalayan range, had not risen to more than a moderate height, and would have supported a luxuriant sub-tropical flora and fauna. The Upper Miocene deposits of northern and central India, and Burmah, agree in their mammalian remains with those of central and southern Europe, while closely allied forms of elephant, hyæna, tapir, rhinoceros, and Chalicotherium have occurred in North China; leading us to conclude that one great fauna then extended over much of the Oriental and Palæarctic regions. Perim island at the mouth of the Red Sea, where similar remains are found, probably shows the southern boundary of this part of the old Palæarctic region in the Miocene period. Towards the equator there would, of course, be some peculiar groups; but we can hardly doubt, that, in that wonderful time when even the lands that stretched out furthest towards the pole, supported a luxuriant forest vegetation, substantially one fauna ranged over the whole of the great eastern continent of the northern hemisphere. During the Pliocene period, however, a progressive change went on which resulted in the complete differentiation of the Oriental and Palæarctic faunas. The causes of this change were of two kinds. There was a great geographical and physical revolution effected by the elevation of the Himalayas and the Thibetan plateau, and, probably at the same time, the northward extension of the great Siberian plains. This alone would produce an enormous change of climate in all the extra-tropical part of Asia, and inevitably lead to a segregation of the old fauna into tropical and temperate, and a modification of the latter so as to enable it to support a climate far more severe than it had previously known. But it is almost certain that, concurrently with this, there was a change going on of a cosmical nature, leading to an alteration of the climate of the northern hemisphere from equable to extreme, and culminating in that period of excessive cold which drove the last remnants of the old sub-tropical fauna beyond the limits of the Palæarctic region. From that time, the Oriental and the Ethiopian regions alone contained the descendants of many of the most remarkable types which had previously flourished over all Europe and Asia; but the early history of these two regions, and the peculiar equatorial types developed in each, sufficiently separate them, as we have already shown. The Malayan sub-region is that in which characteristic Oriental types are now best developed, and where the fundamental contrast of the Oriental, as compared with the Ethiopian and Palæarctic regions, is most distinctly visible.
- As so many typical Malay groups are absent only from the Philippines, I have adopted the term "Malaya," to show the distribution of these, using the term "Indo-Malaya" when the range of the group includes the Philippines. This must be remembered when consulting the tables of distribution at the end of this chapter.