ART. XXVII-CATALOGUE OF THE LAND AiND FRESH-WATER 

 SHELLS OF NEBRASKA. 



By Samuel Aughey, Ph. D. 



PREFACE. 



This catalogue of the laud aud fresb-water shells of Nebraska is the 

 fruit of mauy years' study of the natural history of the State. It 

 would have been easy to greatly extend the number of kinds, as the 

 many different forms of some species, and which have been described 

 as distinct by conchologists, are well represented in the State. For 

 example, Limncea paliistris Miill. has the forms L. 7iuttalKana Lea, L. 

 elodes Gould, L. expansa Hald. As these shells, however, are, in the 

 opinion of W. S. Binney, all different forms of the same species, 

 they are included in L. palustris Miill. In hearty sympathy with the 

 movement to reduce the number of species, I have placed the suspected 

 accidental variations under the name which the species first received. 



I have the least confidence in the completeness of my collection of 

 Unios. Many of the rivers of Nebraska have for long distances muddy 

 bottoms. I have often waded in these streams for many miles without 

 finding a single Unio, and then, coming on a limestone bottom, have 

 found it almost covered with individuals belonging to a few species. As 

 the one-tenth of the distances have not yet been explored, many species 

 not included in this list will yet be discovered. It will be seen that a 

 few species of the family Strepomatidce are given. It was supposed 

 by Tryon that none of this large family existed in this region. As I 

 was hunting shells here for years before any rewarded my search, many 

 more doubtless remain to be added to this short list. It was thought 

 best to give the principal localities for the shells. I am under obliga- 

 tions to Lawrence Bruner, of West Point, for Unios from the Elkhorn, 

 and for Helices from other i)ortions of the State. Most of all, am I under 

 obligations to a member of my own family, who most efficiently aided 

 me in making my collections and in classifying them, and who, bj' her 

 constant encouragement, made it possible for this work to be done. 



