SECOND SERIES: PULMONATA. 



MANUAL 



OF 



T 



STRUCTURAL AND SYSTEMATIC. 



WITH ILLUSTRATIONS OF THE SPECIES. 



' BY GEORGE W, TRYON, JR. 



CONTINUED BY 



HENRY A. PILSBRY. 



CONSERVATOR OF THE CONCHOLOGICAL SECTION OF THE ACADEMY 

 NATURAL SCIENCES OF PHILADELPHIA. 



~Vol. VI. 



HELICID^E, Vol. IV. 



PHILADELPHIA: 

 Published by the Conehological Section, 



ACADEMY OF NATURAL SCIENCES. COR. IQTH AND RACE STS. 



1890. 



