.vX 





5^ 



Number 



-f 



"Si 



MONOGRAPH 



FRESH-WATER UNIVALVE MOLLUSCA 



UNITED STATES, 



(in contixuation of prof. s. s. haldeman's work, published under 

 the above title.) 



By GEORGE W. TRYON, Jr. 



TURBID^. 

 PHYSADiE. 



PHILADELPHIA: 



PCBLISHED BT 



i The Cotv'chological Section of the Academy of Natural Sciences 

 N. W. corner of Broad and Sansora Streets. 



NEW YORK : LONDON : 



B. Westermann & Co., -MO Broadway. Triibner & Co., 60 Paternoster Row. 



BERLIN: MADRID: 



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



PARIS : 

 J. B. Bailliere et Fils, Rue Hautefeuille. 



W-}^' 





i%s/ ^(^ 



