LIST OF SPECIES DISCUSSED AND DESCRIBED. 



NOTE. 



In this list the genera and species are arranged alphabetically according to theil 

 generic and specific designations. The names of genera are printed in small caps 

 The abbreviated titles of publications are as follows: 



J.A.N. S., Journal, (& P.A.N. S., Proceedings) Academy Natural Sciences, Philadel- 

 phia. T. A. P. S., Transactions, {& P. A. P. S., Proceedings) American Philosophical 

 Society, Philadelphia. Obs. Gen. Uuio, Observations on the Genus Unio. Con. Geol., 

 Contributions to Geology. 



The numbers in parentheses ( ) refer to the titles in the first part of this work. 



173 



