SECOND SERIES: PULMONATA. 



MAN UAL 



OP 



ONCHOLOGY: 



STRUCTURAL AND SYSTEMATIC. 



WITH ILLUSTRATIONS OF THE SPECIES. 



BY GEORGE W, TRYON, JR. 



CONTINUATION BY 



HENRY A. PILSBRY, 



CONSERVATOR OF THE CJNCHOLOGICAL SECTION AND PROFESSOR OF MALACOLOGY 

 IN THE ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA. 



Vol. IX. 



(HELICID^E, VOL. 7.) 

 GUIDE TO THE STUDY OF HELICES. 



PHILADELPHIA : 

 3?iablislied by Concliologioal Section 



ACADEMY OF NATURAL SCIENCES, 

 OF PHILADELPHIA. 



1894. 



tJNIVERSITT 



*. Of 



