PREFACE 



The burden of this little volume of '' The Young Collector 

 Series " is to supply a want often felt and often expressed by 

 our younger naturalists, who cannot afford to give the high 

 prices asked for books upon the subject of which it treats. 

 At the same time it must not be looked upon as a finished 

 monograph, nor yet as the only manual that will be needed 

 by the student. As he makes advances in the after-days 

 he will require the larger text- books of Moquin-Tandon, 

 Gwyn Jeffreys, Forbes and Hanley, Rossmassler, and my 

 other work, '^ The Shell-Collector's Handbook for the Field," 

 to wdiich this little volume may serve as an introduction. In 

 the following text, the anatomy of the snail and fresh-water 

 mussel has been given at some length, since the basis of our 

 work must be founded on structural details, and to make 

 these chapters as full as possible, all the available sources 

 of Continental and Home literature have been searched for 

 information. The whole of the species of our land and 

 fresh-water mollusca are described, and their most common 

 varieties are given in footnotes. To my friends, Mr. J. W. 

 Taylor, F.L.S., and Mr. W. Denison Roebuck, F.L.S., I 

 must express my indebtedness for allowing me to reprint 

 here the chapter on distribution from The Journal of Con- 

 cliology, which they have kindly brought up to date for 

 the purposes of this volume ; and I must also express the 

 obligations I owe to that great army of workers (too 



