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THE AMERICAN NATURALIST [Vol. XLV 



Wallace was the foremost really to back up his opinions 

 with valid evidence in setting forth the theory which has 

 proved so .pregnant with suggestion. 



Wallace, who made long journeys among the islands, 

 was the discoverer of the famous "Wallace's Line," as 

 it was named by Huxley, which still, to the present day, 

 is carefully explained in many text-books; though in 

 reality it is disproved, and Wallace himself is not so sure 

 of its existence during the later years of his life. 



According to Wallace's original opinion, based espe- 

 cially upon the distribution of mammals, birds and in- 

 sects, he saw a sharp faunal boundary that could be 

 drawn through the archipelago, which ran to the east- 

 ward of the Philippines, continued between Borneo and 

 Celebes, and on between Bali and Lombok. The fauna to 

 the west of this line was said to be Indian; to the east, 

 Australian. Wallace's dictum is well known, that the 

 faunas of Bali and Lombok are more sharply differenti- 

 ated from one another than those of England and Japan. 



Wallace sought the explanation of these phenomena 

 in the fact that the western half of the archipelago had 

 in earlier times been connected with the Indian main- 

 land, the eastern islands with Australia ; and that they 

 remained joined together until they were divided by 

 narrow arms of the sea. The exceptions which existed 

 Wallace explained in part through transport across 

 water, part as their being remains of the earliest fauna 

 which had lived upon the old land connection between 

 Asia and Australia. 



According to the researches of more recent times, 

 among which should be mentioned especially those of 

 Von Martens, Max Weber, and the Sarasins, it becomes 

 evident that such a sharp boundary as Wallace drew does 

 not exist. Not only is there none where he drew it, but 

 no such line exists anywhere in the archipelago. Of 

 course it is possible to draw a line which apparently 

 bounds the distribution of some single group; and Pel- 

 seneer, upon the ground of the dispersal of molluscs, has 

 constructed a new line which runs eastward of Celebes 



