SECOND SERIES: PULMOIS VTA. 



MANUAL 



OF 



ONCHOLOGY; 



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 OF 

 NATITRAL SCIENCES OF PHILADELPHIA. 



Vol. VIII. 



HELICID^E, Vol. VI. 



PHILADELPHIA : 

 Published by the Conehological Section, 



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

 1892. 



LIBRARY 



UNIVERSITY OF CALIFORNIA 

 DAVIS 



