1 he present work upon Ihe Lamellihranchiala collecled by the Danish Ex- 

 pedition to Siam I'orms the first part of a description of all the testaceous Mollusca 

 of the Gulf of Siam, which I hope to publish gradually, the description being 

 based upon the excellent collections made by Dr. Th. Mortensen during the Danish 

 Expedition 1899-1900. 



I have thought it right to include in the present work all the species which 

 have hitherto been recorded from the Gulf of Siam, even although not collected 

 by the Danish Expedition to Siam. 



I wish heartily to thank Mr. G. M. R. Levinsen of the Zoological Museum of 

 the University of Copenhagen for freely placing the collections of the Museum at 

 my disposal; also 1 am much indebted to my friend at the Zoological Museum, 

 Mr. Ad. S. Jensen, for his unfailing help in searching out material for comparison. 

 Unfortunately, our museum in Copenhagen, although excellent in other respects, 

 is not rich in Asiatic Mollusca which could have been of use to me for the sake 

 of comparison. 1 was therefore verj' much pleased, when, during my sojourn in 

 London (which 1 visited before finishing my work), 1 was able to avail myself 

 of the much richer collections in the British Museum of Natural History, owing 

 to the ready courtesy and kindness of Mr. Edgar Smith, to whom I tender my 

 heartiest thanks. I am also indebted to Messrs. Ph. Dautzenberg, Paris, to the 

 late Professor En. v. Martens of Berlin, and to J. Cosmo Melvill Esq. of Shrews- 

 bury for information and intelligence. 



To Dr. Th. Mortensen, who from the beginning has taken a great interest in 

 my work, and has always been ready with advice and information, I wish to offer 

 my hearty thanks, and also to express my appreciation of the way in which, 

 during the Expedition and often under very difficult circumstances, he has got to- 

 gether such excellent collections, which have in so many ways enriched zoological 

 science with valuable material. 



Copenhagen, December iyU8. 



Herm. Lynge. 



13* 



