7-7* 



SECOND SERIES: PULMONATA. 



MANUAL 



OF 



CONCHOLOGY 



STRUCTURAL AND SYSTEMATIC. 



WITH ILLUSTRATIONS OF THE SPECIES. 



FOUNDED BY 



GEORGE W. TRYON, JR. 



CONTINUED BY 



HENRY A. PILSBRY, Sc.D., 



SPECIAL CURATOR OF THE DEPARTMENT OF MOLLUSCA OF THE ACADEMY OF 

 NATURAL SCIENCES OF PHILADELPHIA. 



VOL. XX. 



C^ECILIOIDES, GLESSULA AND PARTULIDJE. 



INDEX TO VOLS. XVI-XX. 



PHILADELPHIA: 

 Published by the Conchologieal Department, 



ACADEMY OF NATURAL SCIENCES OF I'H ILADHLPH JA. 



1909-1910. 



