

Number — ^y 



MONOGRAPH 



FRESH-WATER UNIVALVE MOLLUSCA 



UNITED STATES. 



(in continuation of prop. s. s. haldeman's work, PUHMSHKD 

 under the above title.) 



By GEORGE W. TRYON, Jr. 



TURBID^. 

 PHYSAD^. 



PHILADELPHIA: 



Publi.shed by 



The Conchological Section of the Academy of Natural Sciences, 



N. W. corner of Broad and Sansom streets. 



NEW YORK : LONDON : 



B. Westermann & Co., 440 Broadway. Trubner & Co., 60 Paternoster Row. 



BERLIN : M.^DRID : 



Asher & Co., 20 Unter der Linden. C. Bailly-Bailliere, Calle del Principe. 

 PARIS : 

 J. B. Bailliere et Fils, Rue Hautefeuille. 



