PEEFACE TO THE FIRST EDITION. 



It may be necessary in introducing this little volume, to 

 state, that it is strictly conchological, and that it is compiled 

 for the use not only of those who wish to acquire an 

 elementary acquaintance with the subject, but also of authors 

 and others, who, desirous of extending their knowledge and 

 pursuing their researches, require a book of reference, con- 

 taining a general outline of what has been done by those who 

 have trodden the same path before them. It has been 

 thought advisable, for general convenience, to arrange the 

 principal part of the information in alphabetical order; adding 

 tables of the systems of Lamarck and De Blainville, to 

 facilitate the systematic pursuit of the science. 



Persons of the class first alluded to, will find great assistance 

 in the explanation of technical words, their application being 

 further illustrated, in most cases, by a reference to the 

 figures j and, although they might have been multiplied, it is 

 trusted that enough are given for every useful purpose. 



The definition of the Classes, Orders, Families, and Genera, 

 in the system of De Blainville, and a tabular view, are pre- 

 sented for the use of those who prefer it, or who wish to 

 compare it with that of Lamarck. 



In the explanation of the figures will be found a systematic 

 arrangement of shells, according to Lamarck, including the 

 names of genera established or proposed since the publication 

 of his system. The descriptions of established genera have 

 been rendered as concise and clear as possible. It is hoped 

 that no essential characters are omitted, and that those living 

 authors, whose proposed generic distinctions have been passed 



