GASTROPODA— NATICOPSIDM. 



673 



Family Naticopsid^e * Gr. & Sh. 



LXVII. Cyclora Hall. 



Minute spiral shells of rounded whorls, loosely embracing so as 



to leave deep suture and umbilicus ; surface smooth, lip thin, 



aperture circular. Ordovicic-Devonic. 



210. C. minuta Hall. (Fig. 932.) Ordovicic. 



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Fig. 932. Cyclora minuta, X 6. (After Meek, Pal. Ohio, I.) 



Subglobose, wider than high, with much depressed spire, three 

 rapidly increasing volutions ; suture almost channeled ; umbilicus 

 small. (Possibly pelagic protoconchs of other gastropods.) 



Cincinnati group of Ohio and Kentucky, etc. Abundant. 



LXVIII. Naticopsis McCoy. 

 Oval to globose non-umbilicated shells, with small spire, large 

 body whorl, oval aperture, and with inner lip more or less cal- 

 lous, flattened, and sometimes transversely striated. Operculum 

 non-spiral. Devonic— Triassic. 

 211. N. ziczac Whitf. (Fig. 933.) Mississippi. 



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Fig. 933. Naticopsis ziczac, natural size 

 and enlarged. (After Whitfield, N. Y. 

 Acad. Science Proc. ) 



Fig. 934. Naticopsis ventricosus, 

 opposite views. (After Meek andWorth- 

 en, 111. Geol., V.) 



Small,, whorls regularly though rapidly increasing in size, sur- 

 face of body whorl with marked zigzag striae. 

 Chester (Maxville) of Ohio. 



