In the volumes treating of Bulimiform snails I shall follow the 

 plan of the several later volumes on Helices, endeavoring to make 

 the identification of species as easy as is possible in the present con- 

 dition of conchological science. Although the descriptions are 

 constructed upon a model differing slightly from that of Pfeiffer, 

 and in a tongue less terse, still I have aimed at the concise style and 

 directness of the great German ; and when the material before me 

 rendered it possible, tables or " keys " have been introduced, to 

 further lessen the tedious labor of specific identification. 



A classification of the entire group with anatomical details will 

 be presented upon the completion of the volumes descriptive of the 

 shells, as it seems convenient to make such division rather than to 

 lengthen the text by the inclusion of a consideration of the soft 

 anatomy. As in the Helices, the general classification of Bulimi 

 seems to require fundamental reformation ; and in many cases 

 characters never before used in their taxonomy are herein con- 

 sidered diagnostic of groups. The resulting re-arrangement of 

 species greatly modifies zoogeographic inferences based upon the 

 older groupings, and it is believed throws new light upon the prob- 

 lems of animal distribution. 



H. A. P. 



