120 Memoirs of the Indian Museum. [Voiy. I, 



bridges, changing very much in different periods, at one time reaching Australia, at 

 another New Zealand (Australia in the meantime being separated from the land bridge), 

 while the other end once touched North India, at any other period South India with- 

 out forming in the meantime a connection towards North India. The matter gets even 

 more complex if we now consider also the east- to- west distribution of the Moniligastrids, 

 which suggests a land bridge between the south of India alone and the Malayo-Burmese 

 region, without following the recent track around the northern angle of the Bay of 

 Bengal. There is, in my opinion, only one suitable explanation of this complicated 

 system of different connections — 



The different land bridges, interposed between Australia and New 

 Zealand on the one side and India on the other, were formed by an archi- 

 pelago, resembling the recent Malay Archipelago; thedifferent islands of 

 this old archipelago changing, in the course of geological periods, their 

 outline and their connection with one another, now forming a bridge 

 between two neighbouring islands, now separating the middle part of the former 

 larger island by diving into the sea, the separated parts sometimes again joining with 

 other islands. In their extensive work on the geological history of Celebes, Messrs. 

 SARASIN plead in favour of such changing outline and of a connection between this 

 island and others, constructing different land bridges for the explanation of the com- 

 plex fauna of these islands.^ My hypothesis, stated in the above sentence, fully agrees 

 with the results of the SARASINS' study, but demands an amplification thereof. It 

 demands with great stress the supposition that this archipelago once reached very 

 much farther to the west, forming a connection between Australia, New Zealand 

 and India, just as it now is interposed between Australia and South-East Asia. I go 

 further, asserting that — 



India itself was divided into a number of islands, once being 

 only the western part of a greater archipelago. The distribution of 

 the endemic terrestrial Oligochsetes of India shows clearly that the recent 

 compact mass of land must, in former times, have been divided into isolated prov- 

 inces; the latter were totally isolated in such a manner that no earthworm 

 was able to cross the intermediate space. This is proved clearly by the sharp 

 separation of the recent provinces of endemic terrestrial Oligochsetes, as stated 

 below. (See fig. ix in the text.) We can hardly suppose that these different 

 interspaces between these provinces have been occupied by deserts. Such deserts, 

 indeed, would have been obstacles to the migration of terrestrial Oligochgetes. But 

 these interspaces have been too small and somewhat too constant in shorter geo- 

 logical periods to be regarded as deserts. It is much more probable, indeed almost 

 certain, that they have been straits, dividing the land into a number of islands. 

 There must have been a large island in the north — the position of the Himalayas — 

 probably including the whole Province of Bengal. This " North Indian Island " 

 represents the dominion of the genera Eutyphoeus and Perionychella. Towards the 



' P. & K. SARASIN, Über die Geologische Geschichte der Insel Celebes auf Grund der Thierverbreit- 

 ung, Wiesbaden, 1901. 



