PREFACE. 



In an endeavor to compile a complete census of the mollusca of Michigan, 

 the Conchological Section of the Michigan Academy of Science has found 

 the lack of convenient and accessible literature a most serious obstacle to 

 enlisting the interest of the many teachers and students of biology through- 

 out the state. 



The present catalogue has been prepared in an attempt to supply this 

 want and to furnish a convenient manual, which would not only embody 

 the recent advances in systematic conchology and exhibit the extent of our 

 present knowledge of the fauna of the state and its distribution, but also 

 enable the student to identify his specimens with some reasonable degree 

 of certainty. 



The systematic portion of the work has been adopted verbatim from Pils- 

 bry, Crosse and Fischer, and other recognized authorities. The specific de- 

 scriptions have been prepared with a view to emphasize the distinctive fea- 

 tures of the different forms, and in all cases keys have been supplied as an 

 additional assistance. 



Through the courtesy of the Secretary of the Smithsonian Institution, 

 electrotypes of the excellent figures contained in the various manuals pub- 

 lished by the Institution have been obtained. Other figures as far as pos- 

 sible have been copied from authoritative sources and, w^here both of these 

 failed, original figures have been prepared. 



In the matter of synonymy, the scope of the work is such as to preclude 

 the full presentation that would be expected in a complete monograph. In 

 addition to the citation of the original authority, however, reference has 

 been made to Binney's Manual of American Land Shells, where full details 

 in this particular will be found as to all except the most recently described 

 species. It has also been deemed desirable to include references to the 

 several general catalogues that have been published of the mollusca of the 

 state. 



The writer is under many obhgations to the members of the Michigan 

 Academy of Science, for valuable material shomng the distribution of the 

 different species, and especially to Dr. A. C. Lane and Mr. W. F. Cooper of 

 the State Geological Survey, Mr. R. H. Pettit of the State Agricultural 

 College, Prof. C. A. Davis of the State LTniversity, Dr. R. J. Kirkland and 

 Mr. L. H. Streng of Grand Rapids, Sister M. Catherine of St. Mary's Acade- 

 my, Monroe and Dr. P. E. Marsh of Otter Lake. We also are indebted for 

 much kindly assistance and suggestion, to Dr. H. A. Pilsbry of Philadel- 

 phia, and Mr. George H. Clapp of Pittsburg, Pa., and Dr. V. Sterki of New 

 Philadelphia, Ohio. 



Several important changes in nomenclature having been made since 

 the paper was submitted for publication^, advantage has been taken of the 

 delay in printing to incorporate them and other additional data recently 

 received, thus bringing the subject down to date. 



Detroit, September 1, 1906. BRYANT WALKER. 



