[126] 



6. Vertigo, MUller. Minute, cylindrical apex acuminate,* 



obtuse ; lip expanded, white. Animal without inferior 

 tentacles. 



7. ZooGENiTE9, Morse. Minute, turrited, conical, acutely 



ribbed longitudinally. Ovoviviparous. 



CIONELLA. 



Subgenera. 



ZuA, Leach. Ovate-oblong, imperforate, smooth, pellucid, 

 golden, shining ; aperture small ; lip obtuse, its extremities 

 joined by a callus ; columella more or less truncate. 



AcicuLA, Leach. Elongate, imperforate, whit^e, vitreous, spire 

 turrited, apex slightly obtuse ; aperture oblong, lip simple, 

 acute ; columella subarcuate, truncate at base. 



ZUA, Leach. 

 1. Zua subcylindrica, Chemnitz. 



Plate 14, figure 14. 



Shell oblong-oval, thin, polished, transparent ; whorls 6, 

 slightly convex, apex obtuse, sutures well marked ; aperture 

 oval, longitudinal, lip thickened but not reflected ; umbilicus 

 impervious. Bright amber color. 



Length 7-5, diam. 2-5 mill. CViLiV, 0:::\l. Xch - 



Inhabits from New England and the Middle States to Lake of 

 the Woods and the far Western Territories. 



ACICULA, Leach. 

 1. Acicula acicula, MUller. 



Plate 14, figure 13. 



Cylindrical, acicular, spire attenuated, apex obtuse, suture 

 narrowly margined ; whorls 6 or 7, flat ; aperture narrow, lip 

 acute, columella arcuate. Hyaline, polished. 



Length 4, diam. 1 mill. 



