MANUAL 



OP 



Structural and Systematic. 



WITH n^LUSTPvATIONS OF THE SPECIES. 



By GEORGE W. TRYON, Jr. 



CONTINUATION BY 



HENRY A. PILSBRY, 



Conservator of the Conchologicai. Section of the Academy of 

 NATURAL Sciences of Philadelphia. 



^ol. XV. 



POLYPLACOPHORA, 

 ( Chitons. ) 



ACANTHOCHITID.E, CRYPTOPLACID^ AND APPENDIX. 



TECTIBRANCHIATA. 



PHILADELPHIA : 

 !Publish.ed by Ooncliologioal Section, 



ACADEMY OF NATURAL SCIENCES, 

 OF PHILADELPHIA. 



1893. ^■'■'■ 



K^ 





o K 





