l_oo\ 



loV 

 T 



MAN UAL 



OF 



CONCHOLOGY; 



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 

 NJ.TITRAL SCIENCES OF PHILADELPHIA. 



Vol. XV. 



POLYPLACOPHORA, 



{Chitons.} 



ACANTIIOCHITID.E, CRYPTOPLACID^E AND APPENDIX. 

 TECTIBRANCHIATA. 



PHILADELPHIA : 

 IPu.blish.ed by Concliologioal Secti- 



ACADEMY OF NATURAL SCIENCES, 



OF PHILADELPHIA. 



1893. 



