PREFACE 



Illustrated monographs of "Pupa" have been published by 

 Kuster, 1849, and by Sowerby, 1872. In his Monographia 

 Heliceorum, 1848-1877, Pfeiffer included descriptions of the 

 species then known. The last general work is therefore forty 

 years old. Meantime the number of genera and species has 

 greatly increased, and taxonomic ideas have changed so radi- 

 cally that the classification and nomenclature of this volume 

 bear little resemblance to those of former works. 



Owing to the minute size of many of these shells, the pro- 

 portion of inadequate or erroneous descriptions and of useless 

 or misleading figures in the existing literature is very large. 



The GastrocoptinaB, described in the present volume, is the 

 largest of the half-dozen subfamilies of Pupillidas to be con- 

 sidered in this monograph. It is also the most widely distrib- 

 uted ; so that species from practically all countries are in- 

 cluded here. 



The literature of Pupillidse is extensive, since most faunal 

 papers on land snails contain some species. In treating of 

 European and North American forms, therefore, a selection 

 has been made of the references thought most important. 

 To include references and localities from all local lists, 

 especially in Europe, would unduly increase the size of the 

 work; and while the importance of the material is appre- 

 ciated, its collation may properly be left for faunal works, in 

 which the accuracy of the references can be controlled, and 

 the details of distribution worked out, by investigators having 

 the requisite local knowledge. Outside of the European and 

 North American faunas, the author has aimed to give all 

 references of any value, and all localities which have been 

 published, omitting only mere lists and compilations contain- 

 ing no new information or localities. 



While every care has been taken to omit nothing essential, 

 it cannot be expected that everything of importance has been 

 noted. The author will be grateful for information relating 

 to omissions or errors in this volume. Also for information or 



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