VI ADVERTISEMENT. 



these pages to the mercy of the public), that continual 

 comparisons have been made of the descriptions of dif- 

 ferent writers for the selection of the best; and that 

 scarce in a single case have the characteristics of a shell 

 been given without the shell itself being either in the 

 Author's possession, or before his eyes. 



ABBREVIATIONS. 



B. British. 



W. Wood's Catalogue of SheUs. 



S. Sowerby's Manual of Conchology. 



T. Turton's Manual of Land and Freshwater Shells. 1st edit. 



E. Encyclopedie Methodique. 



The size is expressed by inches. 



