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Shell depressed-oval, thin, obliquely striated, pellucid^ some- 

 what shining, pale horn-colored; spire short, obtuse; suture 

 deep ; whorls 3, convex, the last rather depressed ; the colum- 

 ella scarcely arched, above conspicuously plicate; aperture 

 angularly oval, frequently armed with a small, oblique, white 

 tooth on the parietal wall ; peristome simple, regularly ar- 

 cuate. 



Dimensions. — Long. 15, diam. 7 mill.; aper. 11 mill, longa, 

 medio 5 lata ; anfr. ult. fere 14 mill, longus. 



Habitat. — Put in Bay Island, Lake Erie, (Frank Higgins!) 



Remarhs. — This species is allied to aS'. Salleana, Pfr., S. Hay- 

 deni, W. G. Binn., and especially to S. ovalis, Grould, non 

 Say. Compared with the latter, the last whorl is less convex, 

 the aperture is more angular above, the columella less arcuate, 

 and more distinctly plicate. 



The measurements given are of one of the largest specimens. 

 This is the only North American species in which I have no- 

 ticed the parietal tooth mentioned in the description. Three 

 of my specimens have this tooth, — it is lamelliform, about 1 

 mill, in length at the base, the pointed apex having an eleva- 

 tion of about ^ mill. 



