MANUAL 



OF 



ONCHOLOGY; 



STRUCTURAL AND SYSTEMATIC. 



WITH ILLUSTRATIONS OF THE SPECIES. 



BY GEORGE W. TRYON, JR. 



CONTINUATION BY 



HENRY A. PILSBRY, 



CONSERVATOR OF THE CONCHOLOGICAL SECTION OF THE ACADEMY OF 

 NATURAL SCIENCES OF PHILADELPHIA. 



SCAPHOPODA. 



BY 

 H. A. IPILSBRY and e. SHARP. 



APLACOPHORA. 

 INDEX TO GENERA AND SUBGENERA, VOLUMES II to XVII. 



PHILADELPHIA: 

 Published by Concliological Section 



ACADEMY OF NATURAL SCIENCES, 

 OF PHILADELPHIA. 



1897-8. 



