£^^ 





Number — Q^ 



^^S, 



MOE"OGEAPH 



FRESH-WATER UNIVALVE MOLLDSCA 



UNITED STATES, 



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

 the above title.) 



By GEORGE W. TRYON, Jr. 



TURBID^. 

 PHYSAD^. 



PHILADELPHIA : 



PDBUSHED BT 



The CoNcnoLOGicAL 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 Kow. 



BERLIN : MADRID : 



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



PARIS : 

 J. B. Bailliere et Fils, Rue Hautefeuille. 



'M^-. 



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15^/-^ 



