Hold the shell with its apex uppermost and its mouth towards you. Make sure that the mouth is to the right of the mid-line.
Check whether an operculum is present. If the animal is alive or recently dead, the horny operculum on the body is obvious. However it may be inside the shell mouth and is sometimes lost in old specimens.
Shell without an operculum
in live animals
Shell with an operculum
in live animals
Please click on the appropriate image to continue.