Shell taller than wide
The first thing is to measure it. For details of how to measure, click on the text link.
The next thing is to count the number of whorls. For details of how to do this, click on the text linkt.
Take a note of the measurements and the number of whorls.
If the mouth-edge is simple and the shell is translucent, glossy and horn coloured, like the shell on the left, click on the image for a full description.
If the mouth edge is thickened, and sharply reflected at right angles, like the shell to the right, click on the image for a full description.