FOREWORD 



"Freshwater Isopods (Asellidae) of North America" is the 

 seventh of a series of identification manuals for selected 

 taxa of invertebrates occurring in freshwater systems. These 

 documents, prepared by the Oceanography and Limnology Program, 

 Smithsonian Institution for the Environmental Protection 

 Agency will contribute toward improving the quality of the 

 data upon which environmental decisions are based. 



Additional manuals will include but not necessarily be lim- 

 ited to, freshwater representatives of the following groups: 

 amphipod crustaceans (Gammaridae) , branchiuran crustaceans 

 (^Argulus) , decapod crayfish crustaceans (Astacidae) , leeches 

 (Hirudinea) , polychaete worms (Polychaeta) , freshwater plan- 

 arians (Turbellaria) , aquatic dryopoid beetles (Dryopoidea) 

 and freshwater clams (Sphaeriacea) . 



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