A 
MONOGRAPH 
OF THE 
\ OF THE 
UNITED STATES. 
(IN CONTINUATION OF PROF. 8. S. HALDEMAN’S WORK, PUBLISHED 
UNDER THE ABOVE TITLE.) 
wt wh 
By GEORGE w. TRYON, JR. 
TURBID. 
PHYSAD A. 
PHILADELPHIA: 
Published 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: MADRID: 
Asher & Co., 20 Unter der Linden. C. Bailly-Bailliere, Calle del Principe. 
PARIS: 
J.B. Bailliere et Fils, Rue Hautefeuille. 
