PREFACE. IX 



many obligations to the liberality of labourers in the same 

 field, and heartily thank (as we do all who have assisted 

 in this work), the veteran investigators of British Mollusca, 

 Dr. Fleming, Capt. Thomas Brown, and the Eev. Leonard 

 Jenyns. To Lieut. Thomas, K.N., Mr. Spence Bate, 

 Mr. Barlee, Mr. W. Thomson of London, and Dr. 

 Knapp, we are indebted for extensive information on 

 subjects of much consequence to the completion of our 

 inquiries. To three ladies, viz., the Marchioness of Hast- 

 ings, Mrs. Griffiths, and Mrs. Gulson, we return many 

 thanks for their interesting communications. A long list 

 of friends who have contributed valuable notes or specimens 

 remains unenumerated. Professor Allman, Professor Bell, 

 Dr. Battersby, Mr. Byerly, Mr. W. H. Baily, Mr. Cocks 

 of Falmouth, Mr. Darbyshire, Mr. W. 0. Eyton, Mr. 

 Gibbs, Mr. Howse, Mr. Hyndman, the Rev. T. Hincks, 

 Mr. Hopkins of Dublin, Dr. Johnston of Berwick, Prof. 

 King of Galway, Mr. Lowe of Nottingham, Mr. F. D. 

 Lukis of Guernsey, the Rev. David Landsborough, Mr. 

 Metcalfe, Mr. Mackie of Folkstone, Mr. Pickering, Mr. 

 R. Patterson of Belfast, Mr. Peach, Mr. Reeve of Wor- 

 cester, Mr. Smith of Jordan-hill, Mr. J. de 0. Sowerby, 

 Professor Strickland, and Mr. S. P. Woodward. 



We may have omitted to mention some to whom thanks 

 are equally due, and whose names are mentioned in the 

 body of the work. 



