The Concholofjical Section of the Academy of Natu- 

 ral Sciences of Philadelphia 



Propose to publish by subscription : 



A Monograph of the Fresh-water Univalve Mollusca 

 of the United States, % Prof. s. S. Haldeman, 



1840-44. 



With Continuation, containing the Species discovered 

 and described since that period. % George w. 

 Tryon, Jr. 



This work was originally published by Prof. Haldeman in 

 eight numbers, each illustrated by five colored plates, drawn and 

 carefully colored from nature by Miss Helen E. Lawson, and 

 engraved by the celebrated Alex. Lawson ; being some of the 

 finest Natural History plates ever issued in America. The 

 genera monographed include the following: — 



Paludina, Limnea, Physa, Planorbis, Ancylus, Amnicola, 

 Yalvata and Ampullaria. 



This work has long been out of print, and complete copies are 

 difficult to obtain, bringing as much as $30, gold. Professor 

 Haldeman having presented to the Conchological Section the 

 few odd numbers of his text remaining unsold, together with the 

 use of the copper plates, it is proposed to reprint enough of the 

 text to place about fifty copies in the market. 



The publication of the Monograph was discontinued after the 

 eighth number, leaving it in an unfinished condition ; but Prof. 



