« EelmineJätka »
one peculiar genus, Salpornis, whose affinities are Palaearctic or Oriental.
2. GENERA of WIDE RANGE occuRRING IN CENTRAL INDIA.
Tardus, Monticola, Drymaeca, Cisticola, Acrocephalus, Phylloscopus, Pratineola, Parus, Pycnonotus, Criniger, Oriolus, Dicrurus, Tchitrea, Lanius, Corvus, Zosterops, Hirundo, Cotyle, Passer, Ploceus, Estrilda, Alauda, Calandrella, Mirasra, Ammomanes, Motacilla, Anthus, Picus, Yuna, Centropus, Cuculus, Chrysoccocya, Coccystes, Coracias, Eurystomus, Merops, Alcedo, Ceryle, Halcyon, Upupa, Caprimulgus, Cypselus, Chatura, Columba, Turtur, Pterocles, Coturnia, Turnia';-48 genera.
3. PALEARCTIC 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 Palaearctic 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 Psammophidae and Erycidae, both desert-haunting groups, and almost as much South Palaearctic as African. The genus Tropidococcyx is peculiar to the sub-region, and Aspidura, Passerita and Cymophis 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 Uromastic are Palaearctic; while Chamaeleon 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 subregion; several peculiar monkeys of the genus Presbytes; the Malayan genus Tupaia ; and Platacanthomys, a peculiar genus of Muridae. Birds—Among birds it has Ochromela, a peculiar genus of flycatchers; Phoenicophaës (Cuculidae) and Drymocataphus (Timaliidae), 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, Uropeltidae, 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 Palaearctic forms. Among lizards several genera of Agamidae are peculiar, such as Otocryptis, Lyricoephalus, Ceratophora, Cophotis, Salea, Sitana and Charasia. In the family Acontiadae, 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, Praometha, Ropica, and Serizia, 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 subregion 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 Palaearctic 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 Timaliidae or babbling thrushes; while the equally characteristic Pycnonotidae, or bulbuls, and Treronidae, or thickbilled 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 Palaearctic 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 Palaearctic 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 Cochih China.