144

CENTRAL AND WESTERN ASIA.

[CHAP.

Having once passed the crest of the snowy range, the traveller enters on the arid region of Tibet, where vegetation of every kind is extremely scanty, except in the deep valleys of the Yarú (or Upper Bráhmapútra) and the Indus. On the southern margin of the great table-land north of Sikkim, Dr. Hooker collected only about fifteen or twenty kinds of plants in two days' journey, and similar accounts are given by travellers in Western Tibet. The country, as far as we know anything of it, is stony or sandy, with occasional salt swamps; and except to the east, where the mountains send down great spurs towards the plains of China, and where Huc and Gabet found them covered with forests, and in some low valleys where fruit-trees and poplars are cultivated, trees are not to be met with. The elevated plain of Gobi, as far as is known, is an absolute desert, except along the foot of the ranges that bound it; and such is also the case with the Persian plains, the great salt desert between Irák and Khorassán, and the sandy desert of Kirman. Turkestan too is a sandy desert, except along the banks of the Oxus and the Jaxartes; but the steppes of the Kirghiz to the north are covered with verdure, receiving rainfall from the evaporation of the Caspian.

The most fertile portions of Persia are the mountain slopes bordering the Persian Gulf, and Mazanderan, on the southern shore of the Caspian, with the table-land of Azerbijan. Mr. W. T. Blanford says that from the accounts given by ancient writers, it appears highly probable that 2,000 years ago the population of Persia was much greater and the cultivation more extensive than at the present day, and that this may have been due to the country being more fertile in consequence of the greater rainfall. "Some alteration," he says, "may have been due to the extirpation of trees and bushes, the consequent destruction of the soil, and increased evaporation," (a sequence of cause and effect which has already been explained in Chapter VIII.,) "but this alone will scarcely account for the change which has taken place; " and he thinks it probable that a gradual change in the climate of Central Asia generally has pro

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LAWS OF VEGETABLE DISTRIBUTION.

145

gressed from the time when the great plain north of Persia was under water, when the Black, Caspian, and Aral Seas were united, and when, as Loftus has shown, the plains of Mesopotamia were a part of the Persian Gulf: this gradual drying up of the country being connected with the elevation of the steppe region of Central Asia and of the southern coasts of Persia.

The vegetation of Persia, Syria, and Asia Minor is very different from that of the Indian peninsula, and more resembles that of Southern Europe; and, in the drier parts, that of Africa. It is in these countries that some of the most delicious fruits of Europe, the peach and almond (originally the same fruit), the cherry, walnut, melon, the olive, mulberry, vine and apricot, have their natural home. Forests of oaks cover the mountains of Laristan, but on the drier borders of the deserts, acacias, and mimosæ (including the babúl), asclepiads (of which the common Madár is a familiar example), tamarisks and euphorbias are among the more characteristic plants.

These examples will serve to illustrate how the plants of different countries vary in general character. If several countries connected together have the same kind of climate, the vegetation is either more or less similar throughout, or only varied according to the nature of the soil and exposure; mountain slope, meadow, swamp and sandy plain each bearing its characteristic plants; or there is a graduated passage from one extremity to the other; but any great difference of climate is accompanied by a corresponding change in the character and abundance of the plants. Countries, on the other hand, which are disconnected, and have been so for long geological periods, though they may closely resemble each other in point of climate, have very different kinds of vegetation. There is little in common between Africa and Australia, though some African plants range as far as India, and the climates of some portions of these continents are very similar. In such cases when the plants of the one country are carried to the other, and artificially introduced, they frequently thrive as well as those native

B.G.

L

146

THE ANIMALS OF INDIA.

[CHAP. to the country of their adoption. The common prickly pear (Cactus), which may be met with everywhere on dry waste ground, and the little spiny-leaved poppy (Argemone Mexicana), which is equally common in India, were originally American plants.

Similar remarks apply to animals. Many of the larger animals of India, such as the elephant, the rhinoceros, the lion, leopard, antelope, gazelle and crocodile, are closely related to African forms, though, except in the case of the lion and leopard, not identical with them. Others again, such as the common black bear, are peculiar to India and are not found elsewhere; while the tiger ranges throughout India and the whole of Southern Asia (excepting Arabia), as far north as the Caucasus on the west, and the Amoor in Eastern Asia. The Gibbons, or long-armed tailless apes of Eastern Bengal, are not to be met with anywhere to the westward, but are numerous throughout the Malay peninsula, Sumatra, and Java. The Lungoors or Húnúman monkeys, of which there are several kinds, range throughout India and Ceylon, the Indo-Chinese region, and the Malay peninsula, but do not occur beyond the Himálaya, nor in countries to the west. The loris of Ceylon, the so-called flying lemur of the Malay peninsula, and the slow-paced lemur (Sharmindi billi) of Bengal, are representatives of a family of monkey-like animals which occur most abundantly in Madagascar, and are not to be met with in other parts of the Asiatic continent. On the whole, the fauna (or whole animal world) of India is a mixture of forms; some related to those of Western Asia and Africa, others to those of Eastern or South-eastern Asia, and a few peculiar to the country or with their nearest relations in the islands of the South Indian Ocean and South Africa.

It remains to add a few words respecting Islands; and here we must distinguish between those lying close to continents, with which, at some former time, they have generally been connected, and those which occur isolated, far out in the ocean. Of the first class, called Continental Islands, we have an excellent example in Ceylon, which was origin

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CONTINENTAL AND OCEANIC ISLANDS.

147

ally a part of India, and is now separated from it only by a shallow channel. On the other side of the bay, the Andaman and Nicobar Islands, with the Cocos Islands between the former and Cape Negraïs, are evidently the summits of the submerged portion of a chain of mountains which runs down Arakan to Cape Negraïs and there plunges beneath the sea, rising again in Sumatra, and forming the back-bone, so to speak, of that island. On the other hand, such islands as St. Helena and Ascension in the South Atlantic, the Mauritius and Seychelles in the South Indian Ocean, and the islands of Polynesia in the Pacific, have either never been connected with any continental land, or are the last remnants of a once extensive land-region now all but completely submerged. Coral islands are also of this latter class. All such are distinguished as Oceanic

Islands.

Now in respect of vegetation and their native animal inhabitants, (under which term we include not only quadrupeds, but birds, reptiles, insects, snails, and all other members of the animal kingdom,) these two classes of islands exhibit a striking diversity. The animals and plants of continental islands are either of the same kinds as those of the neighbouring portion of the continent, or are closely related to them. But generally the kinds are less numerous. Ceylon, for instance, is in this way nearly related to the southern extremity of India. But neither the tiger, the hyena, nor the cheetah occur in the island. On the other hand, as is frequently the case in such islands, it possesses some forms, both of animals and plants, which are restricted to it, and are not to be met with on the neighbouring peninsula. Such are two forms of Húnúman monkey, and certain kinds of snails. In like manner the flora and fauna of the Andaman and Nicobar Islands are nearly related to those of the Malay peninsula, but they possess some forms not occurring on the latter, while a much larger number common on the mainland are not to be found on the islands.

With oceanic islands the case is different. The whole number of forms on such islands is in general small, but

148

OCEANIC ISLANDS. MAN.

[CHAP. these are as a rule peculiar, and frequently very unlike those occurring anywhere else. Thus, until visited and colonized by Europeans, New Zealand possessed no species of mammal (or animal that suckles its young), except one kind of rat, but it possessed a peculiar group of wingless birds, some of gigantic size, nothing like which is known to occur elsewhere. Again the Galapagos islands are the only place in the world in which marine reptiles now live; and out of twenty-six kinds of birds which these islands possess, at least twenty-one are peculiar to them. A gigantic kind of tortoise (miscalled Testudo Indica, or the tortoise of India) and a large palm-tree, the seed of which resembles two cocoa-nuts united, are found only on the Seychelles; and a very peculiar kind of gigantic ground-pigeon, the Dodo, formerly lived on the Mauritius; but being incapable of flight, and therefore easily caught and killed, it has long since become extinct.

Man, the highest member of the animal kingdom, with some of the higher forms of which he has perhaps more in common than most persons who are not naturalists are disposed to allow, is found to obey laws of distribution similar to theirs; but owing to his vastly greater power of moving from place to place, and of adapting himself to varying circumstances, his distribution is world-wide. Obstacles, such as mountain chains and oceans, insuperable to them, are overcome by him under the promptings of his superior intelligence. The discovery of fire, and of the means of providing artificially the clothing with which he is not endowed by nature, together with his power of assimilating food of many and varied kinds, enable him to live and reproduce his kind under extreme conditions of climate that would be fatal to creatures less gifted than he. So long as .even savage man has to contend only with those obstacles to his dispersion which are opposed by the natural barriers of land and water, by the necessities of food and raiment, and the enmity of wild animals, his invasion of the unoccupied land of the globe may indeed be retarded but is not stayed. The sterile burning sands of Arabia, the inhospit