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Genus LEUCOCHILA, Albers. 

 1. Leucochila marginata, Say. 



Plate 15, figure 11. 



Ovately turrited, spire rather obtuse, whorls 6, well rounded, 

 smooth ; aperture rounded, with widely reflected lip ; perforate. 

 Dark brown. 



Length 6, diam. 2-5 mill. 



Eastern, Middle and Western States. 



More cylindrical than the following, with wide-margined white 

 lip. 



2. Leucochila fallax, Say. 



Plate 15, figare 10. 



Ovately turrited, apex acuminate ; whorls 6, well rounded, 

 smooth ; aperture rounded, large, lip expanded but not reflected, 

 without teeth ; umbilicus perforate. Dark brown. 



Length 5, diam. 2-5 mill. 



Eastern and Middle States. 



This species, described by Mr. Say as distinct from his P. 

 marginata, has since been confounded with it. I was luckily 

 able to point out the diflierence between them in Am. Jour. Con- 

 chology, i. p. 285. 



3. Leucochila Arizonensis, Gabb. 



Plate 15, figure 12. 



Pupoid or cylindrical, with obtuse apex, suture well impressed ; 

 whorls 5|, convex, smooth, translucent ; aperture guboval, eden- 

 ,tate, lip thickened, strongly reflected, slightly emarginate near 

 the posterior termination ; imperforate. Corneous, lip white. 



Length 5, diam. 2 mill. 



Fort Grant, Arizona. Pike's Peak in the Rocky Mountains. 



