M A N U A 



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 OP 

 N<LTU:RAL SCIENCES OF PHILADELPHIA. 



Vol. XV. 



POLYPLACOPHORA, 



(Chitons.} 



ACANTHOCHITID.E, ^RYPTOPLACIDvE AND APPENDIX. 

 TECTIBRANCHIATA. 



PHILADELPHIA : 

 3?ublisliecl by Concliological Section, 



ACADEMY OF NATURAL SCIENCES, 



OF PHILADELPHIA. 



1893. 



LIBRARY 



UNIVERSITY OF CALIFORNIA 

 DAVIS 



