Shell. Cylindrical, generally thick; aperture irregular, semi-ovate, rounded, and subangulated beneath; margins of outer lip nearly equal and reflected outwardly, unconnected at their upper parts; the plait of the columella interposed between them. Most frequently found in moss in Europe and America. Forty species.

7. Genus Clausilia. Pl. [X].

Animal. See Helix.

Shell. Cylindrical, generally fusiform; summit obtuse, the last whorl smaller than the preceding; aperture irregular, rounded, oval; margin united, and externally reflected. Inhabits dry situations both in Europe and America. Fifteen species.

8. Genus Bulimus. Pl. [X].

Animals of this genus in formation are precisely as the Helix; they are, however, oviparous, producing eggs with the shell containing the animal perfectly matured; they are frequently as large as a pigeon’s egg.

Shell. Oval, sometimes turriculated, oblong; the summit of the spire obtuse, and the last whorl larger than all the others together; aperture oblong, oval, edge disunited; in adults the lip much reflected; columella smooth, with an inflection in the middle, the base entire, not channeled. Inhabits mountainous situations in Europe and America; some beautiful specimens have been found in the woods of Ohio. Sixty-three species.