SIAM AND CAMBODIA 



307 



The tubed operculates attain their maximum, and Cyclophorus 

 is even more abundant than in India. Fresh -water bivalves 

 abound. JDipsas and Fseudodon are common to China, and Unio 

 and Anodonta are profusely represented. A curious resemblance 

 to S. America appears in this group, a single Mycetopus occurring, 

 the only species not Brazilian, while Arconaia appears very closely 

 to approach the Hyria of the same locality. Several genera 

 of the Hydrobia type {Pachydrolia, Jullienia, Chlorostracia) are 

 peculiar. 



Land and Fresli-water Mollusca of the Siamese Province 



(c) The Malay Province includes the peninsula of Malacca 

 south of Tenasserim, and the series of islands beginning with 

 Sumatra and stretching eastward up to the Ke Is., besides 

 Borneo and Celebes. The Philippines form a separate province. 



The Malay province is singularly poor in representative 

 forms, whether we regard it as a whole or consider the islands 

 separately. Xot a single genus, with the exception of Rhodina 

 (Malacca), appears to be peculiar. The contrast with the West 

 Indies is in this respect very striking. Java, for instance, 

 which is well explored, and almost exactly eleven times the size 

 of Jamaica, has about 100 species of land Mollusca, while 

 Jamaica has about 460. 



