^3<^'^ 



CONTENTS. 



Page 

 Introduction ------- v 



List of Authors vii 



Division of the Family Naiades . - - . 6 



Genus Margarita - - - - - - - 10 



Sub-genus Unio - ~ - - - - - 10 



Sub-genus Margaritana ------ 43 



Sub-genus Dipsas -------47 



Sub-genus Anodonta ------ 48 



Sub-genus Pleiodon - - ■ - - - - 55 



Genus Iridina --.----56 



Addenda - - - 61 



