PREFACE. 



The major part of the following volume is occupied by an attempt to 

 give a synonymy of the species of Strepomatida of the United States 







Though supplied with abundant material, and having, besides, access to 

 all the principal collections of these shells, for the purposes of study and 

 comparison, yet the subject is so vast, the species so numerous, and 

 generally scf variable, that the author cannot feel that confidence in 

 having well performed the task he had undertaken, which he would like 

 to experience. 



The results of my investigations, such as they are, are presented hi the 

 hope that they will not prove entirely useless to those who shall pursue 

 the study of these very interesting animals. 



We would advise those who shall possess this volume, to have inserted 

 alternate blank leaves, in binding it, for the purpose of adding species that 

 may hereafter be described, and for corrections of the synonymy. 



We have given a very full Index of species, arranged alphabetically, 

 under the various genera and subgenera adopted by us. This Index will 

 be found much more complete and useful than those given by Mr. Reeve, 

 and by Dr. Brot, as it includes a very large number of species described 

 since the publication of those gentlemen's works. 



April 15th t 1865. 



