Alfred Russel Wallace

“ To get rid altogether of such varied and dominant types of bird-life by any subsequent process of submersion is more difficult than to exterminate mammalia; and we are therefore again driven to our former conclusion—that the present land of Celebes has never (in Tertiary times) been united to the Asiatic continent, but has received its population of Asiatic forms by migration across narrow straits and intervening islands. ”

“ To these important families may be added Asiatic and Malayan genera by the score; but, confining ourselves to these seven ubiquitous families, we must ask,—Is it possible, that, at the period when the ancestors of the peculiar Celebes mammals entered the island, and when the forms of life, though distinct, could not have been quite unlike those now living, it could have actually formed a part of the continent without possessing representatives of the greater part of these extensive and important families of birds? ”

“ The general distribution of the two best known groups of insects—the butterflies and the beetles—agrees very closely with that of the birds and mammalia, inasmuch as Celebes forms the eastern limit of a number of Asiatic and Malayan genera, and at the same time the western limit of several Moluccan and Australian genera, the former perhaps preponderating as in the higher animals. ”

“ It is not single species or even genera, but whole families that are thus absent, and among them families which are pre-eminently characteristic of all tropical Asia. Such are the Timaliidæ, or babblers, of which there are twelve genera in Borneo, and nearly thirty genera in the Oriental Region, but of which one species only, hardly distinguishable from a Malayan form, inhabits Celebes ”

“ This peculiar formation of the sea-bottom probably indicates that this area has been the seat of great local upheavals and subsidences; and it is quite in accordance with this view that we find the Moluccas, while closely agreeing with New Guinea in their forms of life, yet strikingly deficient in many important groups, and exhibiting an altogether poverty-stricken appearance as regards the higher animals. It is a suggestive fact that the Philippine Islands bear an exactly parallel relation to Borneo, being equally deficient in many of the higher groups ”

“ Forming, as it does, the western limit of such typical Australian groups as the Marsupials among mammalia, and the Trichoglossidæ and Meliphagidæ among birds, and being so strikingly deficient in all the more characteristic Oriental families and genera of both classes, I have always placed it in the Australian Region ”

“ Prioniturus (found also in the Philippines) is a genus of parrots distinguished by raquet-formed tail feathers, altogether unique in the order; while Megacephalon is a remarkable and very isolated form of the Australian Megapodiidæ, or mound-builders.
Omitting those whose affinity may be pretty clearly traced to groups still inhabiting the islands of the western or the eastern half of the Archipelago, we find four birds which have no near allies at all, but appear to be either ancestral forms, or extreme modifications, of Asiatic or African birds—Basilornis, Enodes, Scissirostrum, Ceycopsis. ”

“ The anoa, though anatomically allied to the buffaloes, externally more resembles the bovine antelopes of Africa; while the babirusa is altogether unlike any other living member of the swine family, the canines of the upper jaws growing directly upwards like horns, forming a spiral curve over the eyes, instead of downwards, as in all other mammalia. ”

“ Although I have pretty fully discussed its zoological peculiarities and past history in my Geographical Distribution of Animals, it seems advisable to review the facts on the present occasion, more especially as the systematic investigation of the characteristics of continental islands we have now made will place us in a better position for determining its true zoo-geographical relations. ”

“ Even birds, though usually more widely spread, show a corresponding difference, about eleven Malayan families being quite unknown east of Celebes, where six new families make their appearance which are equally unknown to the westward. ”

“ Nearly thirty species of butterflies, belonging to three different families, have a common modification in the shape of their wings, by which they can be distinguished at a glance from their allies in any other island or country whatever ”