PREFACE. 



The following pages form an enlarged and revised edition of " The 

 Land and Freshwater Shells of North America, Part I," published by 

 the Smithsonian Institution in 1869. Subsequently-described species 

 are added. Fuller attention is given in separate chapters to the sub- 

 jects of geographical distribution, organs of generation, jaw and lingual 

 dentition, and classification. In the descriptive portion of the work the 

 speoies are grouped geographically rather than systematically, an ar- 

 rangement which at first seems awkward to our confirmed habits, but 

 which, on consideration, is justified by the fact that the political di- 

 visions of the continent do not agree with the limits of all the various 

 pulmonate faunas. 



In the earlier work referred to above, I obtained permission to add 



the name of my friend Mr. Thomas Bland as co-author, so intimately 



had we been associated in its preparation. It now becomes my painful 



duty to announce his death on August 20, 1885, and to regret the loss 



in my future studies of the assistance received from his absence of 



prejudice, his extended experience, general scientific training, and 



philosophic mind. 



W. G. BINNEY. 



Burlington, N. J., October, 1885. 



