Article V. — List of the Described Species of Fresh Wafer 

 Crustacea from America, North of Mexico. By Lucien 

 M. Underwood, Ph.D. 



INTRODUCTOEY. 



The economic relations of the fresh water Crustacea are 

 rapidly calling them into general notice, since their importance 

 as the natural food supply of many of our most valuable fishes 

 is established beyond question. It has seemed desirable that 

 our scattered literature on this subject should be indexed and 

 made available to students. The following preliminary list is 

 not intended as a complete arrangement of genera and species. 

 A thorough revision of many of these groups must precede any 

 permanent arrangement, and this is not possible at present. 

 It is, therefore, merely an index to the described species, with 

 such references to American and foreign literature as will 

 place the student in a position to make use at once of all that 

 pertains to each species. In case a full synonymy is given in 

 standard works, like those of Leydig, Glaus, P. E. Miiller, 

 Brady, etc., it has not been thought desirable to repeat this 

 synonymy, but merely to refer to the author giving it in full. 

 For this reason all the European papers are not repeated for 

 all the species they describe. In the American literature, how- 

 ever, it has seemed desirable to give every reference to each 

 species, even at the risk of too great repetition. 



The study of our fresh water Crustacea, with that of their 

 marine congeners, commenced with Thomas Say, and has since 

 attracted the attention of over thirty different writers, nearly 

 all of whom have added one or more new species to our lists. 

 Certain groups, like the PlrtjUopoda and Astacida\ have been 

 carefully monographed, and furnish a literature of great value; 

 in others sufficient work has been accomplished to furnish a 

 broad, if not a substantial, basis for further study; while in 



