M A N U A L 



OF 



ONCHOLOGY; 



STRUCTURAL AND SYSTEMATIC. 



WITH ILLUSTRATIONS OF THE SPECIES. 



BY GEORGE W, TRYON, JR. 



Co:;3i:;;VATo:; OF THE CONCHOLOOICAL SECTION OP TUB ACADEMY OF NATURAL 

 SCIENCES OP PHILADELPHIA. 



VOL. VI. 



PLEUROTOMID^. 



PHILADELPHIA: 

 Published by the Author, 



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



1884. 



LIBRARY 



UNIVERSITY OF CALIFORNIA 

 DAVIS 



