KUNGI.. SV. VET. AKADEMIENS HA N I l.l NCA K. HAND 56. V" 2 



II 



In order lo i>;et a proper undcrstanding of the Fauna of Further [ndia and espe- 

 eially tliat one of Siarn, it is necessary to give a short account of the geological conditioE 

 of this continent at the earlier epoques. 



The present Fauna of the Oriental Region apparently has itsorigirj from the epoque 

 which has been ealled the Pliocen. During that period the Indian Peninsula, Further 

 India and the Malay Ärchipela/go constituted a iarge continent which has been ealled 

 the Gomhvana-contment. Australia and New Guinea were, however, already separated 

 from that enormous continent and have therefore developed quite a pcculiar Fauna of 

 their own. 



The eastern part of the Gondvvana-continent appears to have been divided into 

 two different parts: one western with mountains of a type which have been ealled altaic 

 and one southern with another type of mountain chains ealled sinic. 



Fig. 3. Almost- impenetrable brush-jungle noar Hat Sanuk. 



By and by the Fauna got highly developed, but then large parts of the continent 

 started to sink and in such a way the Bay of Bengal was formed. Therefore the Fauna 

 of the Indian Peninsula had to develop quite independent of the Fauna of Further India. 

 In a låter period large revolutions, principally volcanic, destroyed the connection between 

 certain other parts of the Eastern continent and thus the Malay Archipelago was formed. 



The sinic mountains were gradually destroyed and then the transformation of the 

 altaic mountain chains commenced. At that time a great depression occured which 

 formed the Gulf of Siarn. Borneo now became separated from »Sumatra. Java, on the 

 contrary, had probably already before that time been separated from the rest of the con- 

 tinent which is indicated by the lack of several species which are to be f ound on the other 

 Islands of the Malay Archipelago. The further east we go the poorer is the Fauna. This 

 may possibly be due to unfavourable natural conditions at the same time as great vol- 

 canic eruptions prevented the development of a rich Fauna. Another great depression 



