PREFACE 



In this final volume treating of the Pupillidae and allied 

 families their geographic distribution has been discussed, with 

 lists of the species of the several zoogeographic provinces, 

 given for the convenience of those concerned with local faunas. 



The classification of Pupillidae and their allies, formerly 

 based almost wholly upon the shells, has been in large part 

 placed upon a more satisfactory basis by the admirable ana- 

 tomical work of C.-M. Steenberg, Hugh Watson and others, 

 which appeared during the progress of the present mono- 

 graph. Further data contributed by H. Burrington Baker 

 are now presented in pages 191-209, plates 26-28. A revision 

 of the classification of the Pupillidae into subfamilies, accord- 

 ing to the present views of the author, will be found in the 

 Introduction, pages vii-xii. 



I am indebted to Dr. E. Degner, of the Zoologische Staats- 

 institut u. Zoologische Museum, Hamburg, for compiling 

 numerous names omitted from the indices of volumes 24-26. 

 These have been supplied in the index of vol. 27. 



H. A. PiLSBRY. 



Philadelphia, October 10, 1935. 



(iii) 



