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MAY 20 1986 



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Division of Moliusks 

 Sectional Library 



MALAYSIAN LAND AND FRESHWATER MOLLUSCA 



y 



By the Rev. J. E. Tenison-Woods, F.G.S., F.L.S., Hon. Mem. 

 Roy. As. See. (Straits Branch). 



(Plates xxvii.-xxx.). 



Definition op the Region. — The species included in the 

 following list are those indigenous to the Malay Peninsula in the 

 states south of Keddah and the Indian Archipelago, exclusive of 

 New Guinea. With the exception of the arbitrary line dividing 

 the Malay Peninsula, the limits of this region form a province in 

 natural history in the molluscan sub-kingdom. The reason for 

 excluding New Guinea is that its fauna seems to belong more to 

 the Pacific and Australian regions. The Philippine Islands are 

 not included, because they form of themselves a peculiar province 

 with very marked features, entitling them to separate considera- 

 tion. 



The physical geography of the Malaysian region is another 

 reason for considering its pulmonate moUusca separately. The 

 region consists of an immense number of islands of varying sizes, 

 from mere barren granite rocks to continental islands like Sumatra 

 and Borneo. All those that are of any size are densely clothed 

 Avith vegetation. The climate is very hot, moist, and vai'ies but 

 little. Granite is the pi-evailing rock, with overlying palaeozoic 

 strata and a few outliers of Devonian limestone. There are also 

 in Borneo and Sumatra rather extensive developments of carbon- 

 aceous sandstone and a few patches of tertiary limestone. The 

 south-east portion of the region is made up exclusively of modern 

 volcanic rocks. 



It is known that climate, vegetation, and soil have all powerful 

 influences in the development of the land mollusca, which live on 

 decayed leaves and vegetation, flourishing best amid moisture and 



