SYNOPSIS 



OF 



THE FAMILY OF NAIADES. 



The following table of arrangement and synonymy was undertaken 

 purely with the view and in the hope of clearing away the difficulties 

 which had incumbered one of the most interesting families of the 

 MoUusca. In this attempt the author met, while pursuing his task, 

 with obstructions and difficulties which he little anticipated at its com- 

 mencement. The want of some of the books of reference, and the 

 confusion which reigned throughout many of them, sometimes pre- 

 sented obstacles which seemed almost insurmountable. In attempting 

 to establish the synonymy, he has endeavoured to render the strictest 

 justice, and if in any case it is found he has failed to do this, it will be 

 a matter of sincere regret to him. 



In the following tables there will be found in the family 323 recent 

 species as admitted, 29 unknown to me or doubtful, and 22 fossil; in 

 all 374. 



Of the subgenus Unto, there are 235 species in a recent state, and 

 20 which I have not been able to admit as certain ; of fossil species 21. 



B 



