MANUAL 



OF 



NCHOLOGY; 



STRUCTURAL AND SYSTEMATIC, 



WITH ILLUSTRATIONS OF THE SPECIES. 



BY GEORGE W, TRYON, JR. 



CONSERVATOR OK TIIK COM HOLOOICAL SECTION- OF THE ACADEMY OF NATURAL SCIENCES 

 OK PHILADELPHIA. 



VOL. IX. 



SOLARTID^E, IANTHINTD.E, TRICHOTROPID^, SCALARIID.E, 

 CERITHIID.E, PJSSOID.E, LITTORINID.E. 



PHILADELPHIA: 

 Published by tlie Author, 



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



1887, 



