贝壳电子书 > 英文原著电子书 > the malay archipelago-1 >

第38章

the malay archipelago-1-第38章

小说: the malay archipelago-1 字数: 每页4000字

按键盘上方向键 ← 或 → 可快速上下翻页,按键盘上的 Enter 键可回到本书目录页,按键盘上方向键 ↑ 可回到本页顶部!
————未阅读完?加入书签已便下次继续阅读!



 few of the best known and most remarkable families of birds as a sample of the conclusions furnished by the entire class。

The birds of the Indo…Malay region have a close resemblance to those of India; for though a very large proportion of the species are quite distinct; there are only about fifteen peculiar genera; and not a single family group confined to the former district。 If; however; we compare the islands with the Burmese; Siamese; and Malayan countries; we shall find still less difference; and shall be convinced that all are closely united by the bond of a former union。 In such well…known families as the woodpeckers; parrots; trogons; barbets; kingfishers; pigeons; and pheasants; we find some identical species spreading over all India; and as far as Java and Borneo; while a very large proportion are common to Sumatra and the Malay peninsula。

The force of these facts can only be appreciated when we come to treat the islands of the Austro…Malay region; and show how similar barriers have entirely prevented the passage of birds from one island to another; so that out of at least three hundred and fifty land birds inhabiting Java and Borneo; not more than ten have passed eastward into Celebes。 Yet the Straits of Macassar are not nearly so wide as the Java sea; and at least a hundred species are common to Borneo and Java。

I will now give two examples to show how a knowledge of the distribution of animals may reveal unsuspected facts in the past history of the earth。 At the eastern extremity of Sumatra; and separated from it by a strait about fifteen miles wide; is the small rocky island of Banca; celebrated for its tin mines。 One of the Dutch residents there sent some collections of birds and animals to Leyden; and among them were found several species distinct from those of the adjacent coast of Sumatra。 One of these was a squirrel (Sciurus bangkanus); closely allied to three other species inhabiting respectively the Malay peninsula; Sumatra; and Borneo; but quite as distinct from them all as they are from each other。 There were also two new ground thrushes of the genus Pitta; closely allied to; but quite distinct from; two other species inhabiting both Sumatra and Borneo; and which did not perceptibly differ in these large and widely separated islands。 This is just as if the Isle of Man possessed a peculiar species of thrush and blackbird; distinct from the birds which are common to England and Ireland。

These curious facts would indicate that Banca may have existed as a distinct island even longer than Sumatra and Borneo; and there are some geological and geographical facts which render this not so improbable as it would at first seem to be。 Although on the map Banca appears so close to Sumatra; this does not arise from its having been recently separated from it; for the adjacent district of Palembang is new land; being a great alluvial swamp formed by torrents from the mountains a hundred miles distant。

Banca; on the other hand; agrees with Malacca; Singapore; and the intervening island of Lingen; in being formed of granite and laterite; and these have all most likely once formed an extension of the Malay peninsula。 As the rivers of Borneo and Sumatra have been for ages filling up the intervening sea; we may be sure that its depth has recently been greater; and it is very probable that those large islands were never directly connected with each other except through the Malay peninsula。 At that period the same species of squirrel and Pitta may have inhabited all these countries; but when the subterranean disturbances occurred which led to the elevation of the volcanoes of Sumatra; the small island of Banca may have been separated first; and its productions being thus isolated might be gradually modified before the separation of the larger islands had been completed。

As the southern part of Sumatra extended eastward and formed the narrow straits of Banca; many birds and insects and some Mammalia would cross from one to the other; and thus produce a general similarity of productions; while a few of the older inhabitants remained; to reveal by their distinct forms; their different origin。 Unless we suppose some such changes in physical geography to have occurred; the presence of peculiar species of birds and mammals in such an island as Banca is a hopeless puzzle; and I think I have shown that the changes required are by no means so improbable as a mere glance at the map would lead us to suppose。

For our next example let us take the great islands of Sumatra and Java。 These approach so closely together; and the chain of volcanoes that runs through them gives such an air of unity to the two; that the idea of their having been recently dissevered is immediately suggested。 The natives of Java; however; go further than this; for they actually have a tradition of the catastrophe which broke them asunder; and fix its date at not much more than a thousand years ago。 It becomes interesting; therefore; to see what support is given to this view by the comparison of their animal productions。

The Mammalia have not been collected with sufficient completeness in both islands to make a general comparison of much value; and so many species have been obtained only as live specimens in captivity; that their locality has often been erroneously given; the island in which they were obtained being substituted for that from which they originally came。 Taking into consideration only those whose distribution is more accurately known; we learn that Sumatra is; in a zoological sense; more neatly related to Borneo than it is to Java。 The great man…like apes; the elephant; the tapir; and the Malay bear; are all common to the two former countries; while they are absent from the latter。 Of the three long…tailed monkeys (Semnopithecus) inhabiting Sumatra; one extends into Borneo; but the two species of Java are both peculiar to it。 So also the great Malay deer (Rusa equina); and the small Tragulus kanchil; are common to Sumatra and Borneo; but do not extend into Java; where they are replaced by Tragulas javanicus。 The tiger; it is true; is found in Sumatra and Java; but not in Borneo。 But as this animal is known to swim well; it may have found its way across the Straits of Sunda; or it may have inhabited Java before it was separated from the mainland; and from some unknown cause have ceased to exist in Borneo。

In Ornithology there is a little uncertainty owing to the birds of Java and Sumatra being much better known than those of Borneo; but the ancient separation of Java as an island is well exhibited by the large number of its species which are not found in any of the other islands。 It possesses no less than seven pigeons peculiar to itself; while Sumatra has only one。 Of its two parrots one extends into Borneo; but neither into Sumatra。 Of the fifteen species of woodpeckers inhabiting Sumatra only four reach Java; while eight of them are found in Borneo and twelve in the Malay peninsula。 The two Trogons found in Java are peculiar to it; while of those inhabiting Sumatra at least two extend to Malacca and one to Borneo。 There are a very large number of birds; such as the great Argus pheasant; the fire…backed and ocellated pheasants; the crested partridge (Rollulus coronatus); the small Malacca parrot (Psittinus incertus); the great helmeted hornbill (Buceroturus galeatus); the pheasant ground…cuckoo (Carpococcyx radiatus); the rose…crested bee…eater (Nyctiornis amicta); the great gaper (Corydon sumatranus); and the green… crested gaper (Calyptomena viridis); and many others; which are common to Malacca; Sumatra; and Borneo; but are entirely absent from Java。 On the other hand we have the peacock; the green jungle cock; two blue ground thrushes (Arrenga cyanea and Myophonus flavirostris); the fine pink…headed dove (Ptilonopus porphyreus); three broad…tailed ground pigeons (Macropygia); and many other interesting birds; which are found nowhere in the Archipelago out of Java。

Insects furnish us with similar facts wherever sufficient data are to be had; but owing to the abundant collections that have been made in Java; an unfair preponderance may be given to that island。 This does not; however; seem to be the case with the true Papilioni

返回目录 上一页 下一页 回到顶部 0 0

你可能喜欢的