Identifying British freshwater snails: Shell taller than wide

Shell shape taller than it is wide. For details of how to measure shells, click here.

Place the shell so that its apex is uppermost and its mouth is towards you. Is the mouth to the right of the mid-line, or is it to the left?

Is the shell sinistral
(coiled in a left-handed fashion) as above?

Or is it dextral
(coiled in a right-handed fashion) as here?

Please click on the appropriate image to continue