MANUAL 



CONCHOLOGY 



STRUCTURAL AND SYSTEMATIC. 



WITH ILLUSTEATIONS OF THE SPECIES. 



FOUNDED BY 



GEORGE W, TRYON, JR. 



CONTINUED BY 



HENRY A. PILSBRY, Sc.D., 



SPECIAL CURATOR OF THE DEPARTMENT OF MOLLUSCA, ACADJCMT or 

 NATURAL SCIENCES OF PHILADELPHIA. 



VOL. XVIII. ff UN ,J 

 ACHATINID.E : STENOGYRIN^ AND CCELIAXIN^. 



PHILADELPHIA: 

 Published by the Conehologieal Department, 



ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA. 

 1906. 



