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Show 428 ISLAND LIFE. (PAUT IT. spec·w s; and we may be sure that at tho time when such animals as apes and buffaloes existed, the A~iatic continent swa.rmed with varied forms of mammals to qmte as groat an extent as Borneo does now. If the portion of separated land had been anythinO' like as large as Celebes now is, it would certainly have pre;erved a far more abu~dant and varied ~auna. To explain the facts we have the ch.01ce ?f two th~ones ;either that the original island has smr.e 1ts separatiOn been greatly reduced by submersion, so as to lea~ to. t~e extinction of most of the higher land animals; or, that tt ongmally formed part of an independent land stretching eastwar~, and was only united with the Asiatic continent for a short penod, or perhaps even never united at all, but so connected · by intervening islands separated by narrow straits that a few mammals might find their way across. The latter supposition appears best to explain the facts. The three animals in question are such as might readily pass over narrow straits from island to island; and we are thus better enabled to understand the complete absence of the arboreal monkeys, of the Insectivora, and of the very numerous and varied Carnivora and Rodents of Borneo, all of which are entirely unrepresented in Celebes by any peculiar and ancient forms except the squirrels. The question at issue can only be finally determined by geological investigations. If Celebes has once formed part of Asia, and participated in its rich mammalian fauna which has been since destroyed by submergence, then some remains of this fauna must certainly be preserved in caves or lat~ Tertiary deposits, and proofs of the submergence itself will be found when sought for. If, on the other hand, the existing animals fairly represent those which have ever reached the island, then no such remains will be discovered, and there need be no evidence of any great and extensive subsidence in late Tertiary times. Birds of Celebes.-Having thus clearly placed before us the problem presented by the mammalian fauna of Celebes, we may proceed to see what additional evidence is afforded by the birds, and any other groups of which we have sufficient information. About 16± species of true land-birds are now CHAP. XX.] CELEBES. 420 known to inhabit the island of Celebes itself. Considerably more tha~ half of these (ninety-four species) are peculiar to it; twenty-mne are found also in Borneo and the other Malay Islands, to which they specially belong; while sixteen are common to the Moluccas or other islands of the Australian reO'ion · the . d 0 ' remam er being species of wide range and not characteristic of either division of the Archipelago. \V e have here a large preponderance of western over eastern species of birds inhabiting Celebes, though not to quite so great an extent as in the mammalia; and the inference to be drawn from this fact is, simply, that more birds have migrated from Borneo than from the Moluccas-which is exactly what we might expect both from the greater extent of the coast of Borneo opposite that of Celebes, and also from the much greater richness in species of the Bornean than the Moluccan bird-fauna. It is, however, to the relations of the peculiar species of Celebesian birds that we must turn, in order to ascertain the origin of the fauna in past times; and we must look to the source of the generic types which they represent to O'ive us this information. The ninety-four peculiar species above noted belong to about sixty-six genera, of which about twenty-three are common to the whole Archipelago, and have therefore little significance. Of the remainder, twelve are altogether peculiar to Celebes; twenty-one are Malayan, but not Moluccan or Australian; while ten are Moluccan or Australian, but not Malayan. This proportion does not differ much from that afforded by the non-peculiar species; and it teaches us that, for a considerable period, Celebes has been recei vi nO' immiO'rants from all sides, many of which have had time to bec~me m~dified into distinct representative species. These evidently belong to the period during which Borneo on the one side, and the Moluccas on the other, have occupied very much the same relative position as now. There remains the twelve peculiar Celebesian genera, to which we must look for some further clue as to the origin of the older portion of the fauna ; and as these are espe?ially interesti~g we must examine them somewhat closely. B~rd-types pecuhar to Celebes.-First we have Artamides, one of the Campephaginro or caterpillar-shrikes-a not very well- |
