SECOND SERIES: PULMONATA. 



MANUAL 



OF 



CONCHOLOGY 



STRUCTURE 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 OP 

 NATURAL SCIENCES OF PHILADELPHIA. 



VOL. XX. 



0/ECILIOIDES, GLESSULA AND PARTULID^. 



INDEX TO VOLS. XVI-XX. 



PHILADELPHIA: 

 Published by the Conehologieal Department, 



ACADEMY OF NATURAL SCIENCES OP PHILADELPHIA. 



1909-1910. 



