I 2 



the Indo-Pacific or with species from the adjacent Australian Région. The remainder of the 

 collection consists of the widely distributed Indo-Pacific species, and thèse do not call for any 

 spécial remarks. 



I hâve hère to record my great indebtedness to my chief Lt.-Col. R. B. Seymour Sewell, 

 Director, Zoological Survey of India, for permission to undertake this work. I hâve also to thank 

 Dr. W. T. Calman, Keeper of Zoology, British Muséum (Natural History), London, and Mr. 

 G. C. RoBSON, Deputy Keeper and Incharge of Molluscs in the same Institution for spécial 

 facilities for work and comparing of the "Siboga" material with the very rich collections stored 

 in the British Muséum. My grateful thanks are also due to the Library Staff of the British 

 Muséum for their unfailing kindness in acceding to my numerous demands at ail times. Mr. J. 

 R. LE B. ToMLiN and Mr. R. C. Winckworth also assisted me in various ways, and were ever 

 ready to help me with material and information from their private collections. Finally I hâve 

 to thank Professer Max Weber, the leader of the "Siboga" Expédition for entrusting this 

 valuable collection to me for study, for his continued interest in the progress of the work, for 

 his very valuable suggestions in connection with the préparation of the report and above ail 

 for seeing the work through the press. \ 



