MANUAL 



OF 





Structural and Systematic. 



WITH ILLUSTPvATTONS OF THE SPECIES. 



By GEORGE W. TRYON, jR. 



l'o>-SERVATOi: i.r Tin: Coxcholooic.vl Sectiox op tii:; AcAnEMY <ip IVATrRAi, 



SolENCE.i OF PlItl.ADEr.VIIIA. 



VOT.. IV. 



NASSID^, TURBINELLID^E, VOLUTID/E, MITRIDyE. 



PHILADELPHIA: 

 Publish lie cl by tlio Aiitlioi-, 



Academy of Natural Sciences. Cor. IStm & Race £ts. 



1882. 



^"•'-j?/ 



