When I am measuring a large lot of snail shells I often need to know which measurement is associated with which shell so that if I need to re-examine the shells in the future for whatever reason, I will not have to measure them again. Frequently, there are also specimens with unusual features that need to be set aside for further examination. The easiest thing to do is to write numbers on the shells. But that is feasible only if the shells are large. One may also keep each shell in a numbered gelatin capsule if there are enough capsules available.
Another solution is to place the shells in coded positions inside a suitable container. Corrugated cardboard works well for that purpose. I usually number each column and assign a letter to each row. Here are some Albinaria caerulea shells lined up in the grooves of a sheet of corrugated cardboard. Of course, the locality information must always be kept with the shells.
Sometimes I use a small box filled with sand to position large shells for photography. Recently I learned that paleontologists use large sandboxes when they are assembling fossil bones from fragments (examples from the VA Museum of Natural History Vertebrate Paleontology Lab are here and here). So a few day ago when I was measuring some shells of Orculella ignorata, a small land snail from Turkey and the adjacent Greek Islands, I thought of using a small sandbox to line up the shells.
The mean shell height of this lot of Orculella ignorata was 6.6 mm.
It worked well. The next time I am at a beach I have to remember to get more sand. I also have to stock up on Sour Alerts Extreme Orange Sour Candies.