MANUAL 



OF 



CONCHOLOGY; 



STRUCTURAL AND SYSTEMATIC. 



WITH ILLUSTRATIONS OF THE SPECIES. 

 *, ^v" 



IUNIVEKSIT 



BY GEORGE W. TRYON, JR. 



;o:;r,^:;vATo:i OF THE COXCHOLOGICAL SECTION OF THE ACADEMY OF NATURAL 

 SCIENCES OF PHILADELPHIA. 



VOL. VI. 



CONID^, PLEUROTOMID^E. 



PHILADELPHIA: 

 Published by the Author, 



ACADEMY OF NATURAL SCIENCES, COR. I9TH & RACE STS. 



1884. 



