456 ISLAND LIFE part ii 



its flat projecting muzzle, large superciliary crests, and 

 maxillary ridges. 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. An approach to 

 this peculiarity is made by the African wart-hogs, in 

 which the upper tusk grows out laterally and then curves 

 up ; but these animals are not otherwise closely allied to 

 the babirusa. 



ProhaUe Derivation of the Mammals of Celebes. — It is 

 clear that we have here a group of extremely peculiar, and, 

 in all probability, very ancient forms, which have been 

 preserved to us by isolation in Celebes, just as the mono- 

 tremes and marsupials have been preserved in Australia, 

 and so many of the lemurs and Insectivora in Madagascar. 

 And this compels us to look upon the existing island as a 

 fragment of some ancient land, once perhaps forming part 

 of the great northern continent, but separated from it far 

 earlier than Borneo, Sumatra, and Java. The exceeding 

 scantiness of the mammalian fauna, however, remains to 

 be accounted for. We may be sure that at the time when 

 such animals as apes and buffaloes existed, the Asiatic 

 continent swarmed with varied forms of mammals to quite 

 as great an extent as Borneo does now. If the portion of 

 separated land had been anything like as large as Celebes 

 now is, it would certainly have preserved a far more 

 abundant and varied fauna. To explain the facts we have 

 the choice of two theories : — either that the original island 

 has since its separation been greatly reduced by submersion, 

 so as to lead to the extinction of most of the higher land 

 animals ; or, that it originally formed partof an independent 

 land stretching eastward, and was only united with the 

 Asiatic continent for a short period, 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 



