Original Combination:

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Original Description:

Testa superni obtuso-conica, inferrit subinflatd, nitida, corned, longitudinaliter striata, late umbilicata ; anfractibus senis; aperturd lunatd, tridentatd. Shell above obtusely conical, below somewhat inflated, shining, horn-colour ; longitudinally striate, widely umbilicate; whorls six; aperture lunate, three-toothed. Hab. Ohio. Mr Dorfeuille, Cincinnati. My Cabinet. Diam. -3, Length -2 of an inch. Remarks. — I adopt Mr Say's genus Polygyra, believing the division, though very artificial, quite as good as many made by Lamarck. This species has, like Polygyra fatigiat a (Say) and P. plicata (Say), one large tooth on the left lip and two smaller ones on the right lip. It differs from the first in not being carinate, from the last in being larger and having larger striae. In the Dorfeuilliana the tooth on the left lip is large and square, with an indentation in the centre. The view into the mouth is nearly obstructed by the teeth, leaving, to appearance, three nearly square apertures. The superior part of the shell is striate, while the inferior part is nearly smooth, and exhibits two volutions. I have seen but a single specimen, which I believe is the only one obtained by Mr Dorfeuille, who obligingly sent it to me.