A Manual of Conchology / According to the System Laid Down by Lamarck, with the Late Improvements by De Blainville. Exemplified and Arranged for the Use of Students.

by Thomas Wyatt

A. Sileni. Silenus’s Ear.

Species very small, without plaits or teeth.

11. Cyclostoma. Twenty-eight species.

A terrestrial shell, varying considerably in form, but distinguished by a round aperture, reflected lip, and horny operculum.

Shell more or less elevated, volutions rounded, summit papillose; aperture round, the edges united circularly and reflected; the left having its origin very detached from the spire.

Operculum calcareous, complete, not spiral; summit sub-central.

Cyclostoma planorbula.

C. volvulus.

C. carinata.

C. sulcata.