XXV.-THE CRUSTACEA OF THE FRESH WATERS OF THE 

 UNITED STATES. 



By Sidney I. Smith. 



A-SraOPSIS OF THE HIGHER FRESH- WATEIJ CRUSTACEA 

 OF THE NORTHERN UNITED STATES. 



The following synopsis is intended to include all the species of deca- 

 pod and tetradecapod Crustacea known to inhabit the fresh waters of 

 the Northern United States east of the Mississippi River. It has been 

 limited to this particular region, because there has been at band no 

 material of any importance from other parts of the country, and because 

 very few species have been described from localities outside of the region 

 included. I should, perhaps, except from this statement the numerous 

 species of Astacidw, but these have been so recently monographed by 

 Professor Hagen that -it seems needless to repeat an account of them 

 here. The fresh-water Crustacea are of great economic importance as 

 ' food for very many, if not all, our fresh- water food-fishes 5 and on this 

 account, as well as for purely scientific reasons, I hope this imperfect 

 synopsis will be of service to all those interested in the subject, and 

 trust It wdl hasten the preparation of a more complete work, including- 

 all the species of the United States. 



I am indebted to Mr. Oscar Harger for the descriptions of the species 

 of AseUus and Asellojysis. 



MACRURA. 



Family Astacidw. 

 The following list of the species of this family I have compiled largely 

 trom Dr. Hageu's most valuable work,* to which the reader is referred 

 for the full account of the species. The crawfishes of all the eastern 

 part of the United States belong to the genus Camharus, but the species 

 appear to be quite numerous, and are difficult to distinguish without 

 careful study. 



Cambarus acutus GiKird. 



Proceedings Academy Nat. Sci. Philadelphia, vol. vi, p. 91, 183.1 ; Hagen, op. cit 

 p. 3r., pi. 1, figs. 1-5 ; pi. 2, figs. 106-127 ; pi. 3, figs. 143, 144. 



jg^j^species^^ne_ of the largest of our cr awfishes^jiasjm extensive 



* Illustrated Catalogue Museum Coiup. Zool., No. 3 ; Monograph of the North Ameri- 

 can .istacidie, 1870. 



