— ./-T.^ 4.C/' 



All MfJUtt tH/AUJA 



UNIVERSITY OF MICHIGAN 



PIqU museum of zoology 



Miscellaneous Publications No. 6 



A Synopsis of the Classification of the Fresh- 

 Water MoUusca of North America,""^"^ 

 North of Mexico, 



AND 



A Catalogue of the More Recently 

 Described Species, With Notes 



BY 



BRYANT WALKER 





ANN ARBOR, MICHIGAN 



PUBLISHED BY THE UNIVERSITY 



DECEMBER 30, I918 



