Mollusc-land

By Karen Banton, Assistant Collections and Learning Curator

My second John Ellerman Foundation-funded project has been getting the Colchester mollusc collection in order. Five months. Four cupboards. Lots of molluscs. And a surprising number of corals. Both things I knew very little about.

The mollusc collection is a mix of historical and modern – the historical being made up of shell collections donated to the museum when it first opened and the modern being shells collected in the local area. Many of the older shells are unidentified or have out of date identifications (DNA analysis revealed that many species, decided by shell shape, are in fact one species with different shell appearance). 

What is a Mollusc anyway?

There are three well known groups:

• Gastropods: slugs and snails. They have a single shell. Even the slugs! I didn’t know that slugs had shells, most species have a small shell inside of their body. Shelled slugs have them outside on the end of their bodies.
• Bivalves: shells with two valves, like mussels, oysters, clams and scallops.
• Cephalopods: Squid, octopus and cuttlefish. Squid and cuttlefish have an internal shell.

We also have in our collection:

• Scaphopods: whose shell look like hollow elephant tusks.
• Chitons: their shells look a little like plate amour or a woodlouse (see left)

Squirrelled away in the mollusc drawers were non-molluscs (barnacles, rocks, corals…) you might find at a beach. More surprising were the teeth. And the broken glass tumbler. And a tin filled with hawthorn sprigs… And a pipe. Admittedly, it does have polychaete tubes and barnacles on it. But these are not molluscs and should not be with molluscs.

Karen’s 7 step guide to learning about molluscs

Step 1: Ask for mollusc books for Christmas. Read them. Bring them to work.

Step 2: Find the latest taxonomy for molluscs and what species occur in the UK. The taxonomy is still being worked out. Get in touch with other museums and ask them for advice.

Step 3: Discover that the National Museum Wales has some of the best (free!) resources for UK bivalve identification. They’re also the ones who pointed me to MolluscaBase, the world register of molluscs.

Step 4: The most important step is to fall in love with the National Museum of Wales.

Step 5: Learning you can’t ID non-UK molluscs, buy books on foreign shells.

Step 6: Work out that the Bulimus snail you keep coming across is made up. Use a French book from the 1800s to work out what the species might actually be. It’s not 100% reliable, but it’s better than nothing.

Step 7: Despair at how many snails there are. Seriously. So many. Cry a little. Sigh each time you see another drawer of unidentified snails.

How to reorganise a collection

Step 1: Use useful cheat sheets with the anatomy of snails and bivalves, and pictures of the most common oysters in the collection. Start by identifying shells.

Step 2: Find the most wonderful team of volunteers. They were quick learners and always in high spirits. Their combined efforts documented a third of the collection!

Step 3: After four months of identifying and bagging shells, it was finally time to re-organise.

At the start of my adventure in Mollusc-land the last two cupboards were a mix of corals and molluscs. The first job was banishing all the corals to the fourth cupboard so that all the molluscs were together.

To order the molluscs, and separate native and non-native species, I borrowed as many tables as was possible to fit in the stores. With someone reading out the location and the number of the object, it was time to go fishing for objects. As each shell was removed it was put on the table, and at the end of each family group it was boxed in using masking tape and labelled. These were placed in lined drawers and their new location added to the inventory.

So, after five months, the collections are now in taxonomical order. Perhaps it is not perfect (ideally each species and genus would be separated out). And there is still work left to do (working out what the unidentified shells are).

I now need a little break from molluscs, before I start my next project on Boxstones. So, I’ll take a week and see some family. And no matter what… there will still be molluscs to enjoy!

Colchester mollusc collection facts

• We have 1844 mollusc specimen in our collections.
• There are 861 known native molluscs in the collection.
• There were 511 molluscs that I couldn’t identify enough to work out if they were native or not.
• 64% of our molluscs are gastropods.
• The non-gastropods and non-bivalves make up less than 1% of the collection.
• Of the UK mollusc species, we have represented in our collection, 36% are terrestrial and freshwater gastropods, 29% freshwater bivalves, 20% marine bivalves.

The team

This project couldn’t have been completed without help.

My lovely volunteers Carly, Peter, Philipp and Tania did so much work that without them, I would still be worrying if I’d finish the inventory. Ish, who supported me with my volunteers and helped out in the collections more than once. Sophie gave me advice, moral support and help in documenting the molluscs.

In fact, everyone at Colchester + Ipswich Museums, all of whom have put up with my rants on mollusc taxonomy, appearance and curators illegible handwriting. I was given plenty of excuses to make biscuits and cakes for people in the office. Sugar and tea are how I get through challenges. That and spite. I couldn’t let the molluscs win after all!