SUMMARY. 



In the preceding pages are listed and described twelve orders, 

 twenty-five families, sixt}^ genera, one hundred and four species, and 

 six additional varieties. The following list shows the distribution 

 of these species and varieties among the various families and or- 

 ders. 



There are no definite data concerning two of the species {Ameiu- 

 ri(s hiciistris and Lcptops olharis), but tla.e\ have, no doubt, been 

 taken in the Mississippi and its tributaries. Where a variety form 

 alone is represented and not the species, the variety is enumerated 

 as a species, but when the typical species and the variety occur, 

 the variety is enumerated as one of the six referred to above. 



CLASS MARSIPOBRAI^CUII. 



ORDER HYPEROARTII. 



Family PETKOM YZONID^E. The Lampreys. 



Genus Iclithyomyzon Girard. 



I. concolor (Kirtland). 

 I. castaneus Girard. 



CLASS PISCES. 



ORDER SELACHOSTOMI. 



Family POLYODONTIDiE. The Paddle-fl&hes. 

 Genus Polyodon Lac^pede. 



P. spatlmla (Walbaum). 



ORDER CHONDROSTEI. 



Family ACIPENSEKID^a^. The Sturgeons. 

 Genus Acipeiiser Linnajus. 



A. rubicundus Le Sueur. 

 Genus Scbaphirliynchiis Heckel. 



S. platorynchus (Rafinesque). 



