MANUAL 



OF 





Structural and Systematic. 



WITH ILLUSTRATIONS OF THE SPECIES. 



By GEORGE W. TRYON, jR. 



CONSKRVATOn OF THE CoN* lI()I.O(;i(AL SkCTION OV THK ACAliKMY OF XaTXRAI, SctF.NCF.S 



OF rHILAUEU'lIIA. 



VOL. VIII. 



NATICID.E, CALYPTR^EID^E, TURRITELLTD.E, VERMETTD^, 

 C^X'IDyE, EULIMID^E, Tl'RBOXILLlD.E, 



pyramidelltdj:. 



PHILADELPHIA: 

 Piiblii-^liod by tho Author,,- 



AcADtMV OF Natural Sciences, Ccr. 13th & Racc Sts. 



1880. 



^•'.^^.. 



,'\ 



