Nousan 8/2, Coll 
A 
MONOGRAPH 
OF THE 
FRESH-WATER UNIVALVE MOLLUSCA 
OF THE 
UNITED STATES. 
1 
(IN CONTINUATION OF PROF. 8. 8. HALDBMAN’S WORK, PUBLISHED 
UNDER THE ABOVE TITLE.) 
By GEORGE W. TRYON, Jr. 
TURBIDA. 
PHYSADA. 
PHILADELPHIA: 
‘Published by. 
"Tus CONOHOLOGICAL SECTION OF THE ACADEMY OF NATURAL SOIENCES, 
N. W. corner of Broad and Sansom streets. 
NEW YORK: LONDON: 
B. Westermann & Co., 440 Broadway. Trubner & 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. 
