SECOND SERIES: PULMONATA. 



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 TUE ACADEMY OF 

 NATUHAL SCIENCES OF PHILADELPHIA. 



Vol. VII. 



HELICID^E, Vol. V. 



PHILADELPHIA : 

 Published by the Conehologieal Section, 



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

 1891. 



LIBRARY 



UNIVERSITY OF CALIFORNIA 

 DAVIS 



