PREFACE. 



The question whether another book on the British 

 Mollusca is wanted by the scientific world, when there is 

 at present a complete history of the subject by the late 

 Professor Edward Forbes and Mr. Hanley, is answered by 

 the notoriety of the fact that the price of that admirable 

 work puts it beyond the reach of most naturalists ; and 

 the enterprising publisher of those, as well as the present, 

 volumes was so fully impressed with the necessity of 

 another work at a more moderate price, that he invited 

 me to undertake the task, which I fear I have inefficiently 

 performed. In doing this, however, I have endeavoured 

 to make the present work quite distinct from its 

 predecessor, as may be seen by comparing the two; 

 and those who are not fortmiate enough to possess a 

 copy of '^A History of British Mollusca and their 

 Shells,-'^ and who can afford the money for its purchase, 

 will not regret the expenditure. 



With regard to the animals or soft parts of the 

 Mollusca described in this volume, I have been greatly 



