Spirals in Time: The Secret Life and Curious Afterlife of Seashells

by Helen Scales

  A nautilus interlude

  To catch a nautilus is fairly straightforward: make a wooden or wire trap with an entrance just big enough for a nautilus to swim through; bait the trap with cat food or scraps of chicken, then lower it down into deep water to at least 100 metres (the method does, admittedly, require a lot of rope) and leave it overnight. Scavenging nautiluses will pick up the whiff of food and come to investigate. Once inside the trap, the short-sighted cephalopods can’t find their way back out. All the nautilus hunter need do is return the following morning and pull all that rope back up.

  This is how the commercial trade in nautilus shells is carried out today, with tens of thousands of animals caught and killed each year. Gilded nautilus cups may have fallen out of fashion, but these days people use the spiralling, tiger-striped shells to make all manner of other ornaments, lampshades and buttons. There are even people who eat chambered nautiluses; between 2007 and 2010, Indonesia exported 25,000 nautiluses to supply meat markets in China.

  The Philippines is a major player in the nautilus trade. Exports have fluctuated; in 2008 around 54,000 nautiluses were recorded in trade; the following year the number tripled; then in 2010 the trade dropped again to around 24,500 animals (figures are grouped together for all the Nautilus and Allonautilus species). A lot of these nautiluses end up in the United States. Between 2006 and 2010 more than half a million items were imported to America, most of them whole shells.

  The Philippines was also one of the first places where nautilus fisheries began to collapse. Anecdotal reports suggest that nautiluses have gone locally extinct in the Tañon Strait between the islands of Negros and Cebu. This happened in the 1980s and since then the fishery hasn’t restarted, suggesting that the nautiluses have not recovered. If they had, fishermen would surely be going out to catch them.

  A 2014 study used video cameras baited with chicken to survey nautilus populations in a fishing ground of the Philippines and compared it to three un-fished sites in other countries. Individual nautiluses were identified based on unique patterns of stripes on their shells. The highest numbers were counted in Australia, at Osprey Reef in the Coral Sea (68 nautiluses) and on the Great Barrier Reef (92). Twenty nautiluses were identified at each of two other un-fished sites, Beqa Passage in Fiji and Taena Bank in American Samoa. By contrast, in the Philippines, the drop-down cameras spotted only six nautiluses. Even taking the soak-time of each camera into account, estimates of the total population are still far lower in the Philippines than elsewhere. Several factors could explain these differences, including variety in habitat type and limitations of the filming technique. But most likely is that the Philippines population has been depleted by fishing while the others have so far been left alone.

  These results are no great surprise, given a few basic facts of nautilus biology: they don’t become sexually mature until they are teenagers, at least 15 years old; when they do, a female spends a year incubating eggs inside her shell before a meagre 10 or 15 hatchlings emerge. Compared to many other molluscs, there really is no possibility that the ocean will become overrun by nautiluses any time soon – quite possibly the opposite.

  Based on this latest research, it seems nautiluses could be far less abundant than anyone ever imagined, even in areas where they aren’t being hunted. People have been admiring and collecting their shells for hundreds of years but now the pressure on them could be too high. Many experts are calling for the immediate control of the global nautilus trade to make sure that this narrow branch of the tree of life doesn’t face one mass extinction too many, and finally get snapped off.

  Of gentlemen and disappointment

  Cuming returned to London in June 1840, whereupon he hung up his explorer’s hat once and for all. He spent the rest of his life expanding his shell collections from the comfort of his new home at 80 Gower Street in Bloomsbury, a short stroll from the British Museum. He would still visit auction houses and museums across Europe, but never again departed for exotic, faraway shores.

  He distributed much of his Philippines material among naturalists and collectors – not just shells but thousands of birds, insects, crabs and reptiles, and 130,000 dried plants, which he hoped would impress William Jackson Hooker, the man who would soon be appointed as director of the Royal Botanic Gardens at Kew, and who Cuming had been writing to for years.

  As well as all his plants, Cuming also sent Hooker the journal he wrote during his Philippines sojourn. In the accompanying note, dated May 1841, Cuming refers to his journal as his ‘child’, apologising effusively for his bad spelling and grammar and asking for help in editing and publishing the work. Unfortunately, Cuming had picked the wrong man to ask for assistance. While Cuming was well liked by many throughout his life, there were a few scientists who didn’t seem to take him seriously; Hooker was one of them.

  Hooker rejected Cuming’s work and the journal was lost, perhaps carelessly by Hooker or deliberately by a disappointed Cuming. With the journal gone, Cuming’s hopes of being fully accepted as a gentleman of science were shattered. Perhaps it was his lack of schooling or his refusal to describe any of his collections himself, but throughout his life and for decades afterwards, there were some shell experts who didn’t value Cuming’s work. In 1909, conchologist Charles Hedley described Cuming as ‘an illiterate sailor’ and complained ‘his plans did not regard the advancement of science’. Another shell scientist in 1939 described Cuming’s collection as a ‘pestilential conchological swamp’.

  Many argued that Cuming had done a bad job of labelling his collections with localities of where the shells were found, a vital piece of scientific information. These allegations were rather unfair given the nineteenth-century custom of attaching only brief notes to specimens, with locations often as vague as ‘South China Sea’ or ‘India’.

  On the contrary, it seems Cuming had an encyclopaedic memory for where his shells came from; the only problem was that he kept most of that information in his head, and not written down. People who watched him at work reported how he would lay out parts of his collection on long tables, then dictate notes to an assistant, all from memory.

  There is no doubt that Cuming was incredibly generous with his shells. Dozens of scientists passed through his doors to examine and describe them. One of them was Charles Darwin, and over the course of several years the two men corresponded at length and occasionally met. Cuming identified all of the shells Darwin brought back from the Galápagos, he discussed ideas with him on coral reef formation, and lent him many specimens. One of the most important, although not a mollusc, was Ibla cumingi, a barnacle Cuming brought back from the Philippines. In the introduction to his book A Monograph on the Sub-class Cirripedia, Darwin thanked Cuming for persuading him to spend time looking at barnacles, and said Cuming had ‘placed his whole magnificent collection at my disposal’. Cuming even let Darwin chop up some of his precious specimens. When he dissected Ibla cumingi, Darwin found bizarre miniature male barnacles clamped tightly to the giant females (a little like male argonauts), giving him vital clues as to how sex evolved.

  But Darwin wasn’t always so admiring of Cuming. In 1845 he described him as ‘very difficult to make stick to his work’ in a letter to his friend Charles Lyell. By then, however, Cuming’s health was failing, perhaps from all the years of tropical exploration, which might explain why he was not paying much attention to Darwin. A short time later, Cuming suffered a stroke from which he was not expected to recover.

  In December 1846, a letter arrived at the British Museum from the ailing Cuming offering his great collection of 52,789 shell specimens, including at least 18,867 species. The price for his entire collection was £6,000, equivalent to at least half a million pounds today.

  His offer to the museum was followed by letters from several eminent zoologists including Richard Owen and William Broderip, urging the trustees to buy Cuming’s shells. They pointed out how bothersome it would be if the collection were broken up and lost overseas, scattering this rich sou
rce of study far from British soil. John Edward Gray, keeper of zoology at the British Museum at the time, was less enthusiastic, and perhaps under his influence the museum rejected Cuming’s offer.

  Despite his illness, Cuming lived on a further 20 years until he was 74, with his daughter, Clara Valentina, now by his side. He continued to add to his collection, funding younger men to go on collecting expeditions for him, and he still paid visits to local auction houses. In April 1865 Cuming was spotted in Covent Garden bidding on shells, and was remembered by one collector as a ‘somewhat stout, rubicund, good-humoured looking old man’. A few months later, on 10 August, Hugh Cuming passed away at his home in Gower Street. His hair was a jumble of white curls, his skin creased by years of sun and sea, and he was surrounded by his beloved shells.

  By then, his collection included some 83,000 shells, proof that he had surely achieved his lifelong ambition. This was without doubt the largest and most famous collection of shells then in existence. A great number of them were ones he had found himself throughout his extraordinary adventures, exploring places no other shell-collectors had been, island-hopping, dredging the seabed, dipping in rivers, shaking tree trunks and picking over leaves and rocks. While other collectors and museums would eventually bring together more shells, Cuming’s is still the most impressive collection that one person has amassed. But he didn’t live to witness his final wish coming true, to see his fine collection on display at the British Museum.

  In a room lined with tall mahogany cabinets I can’t decide where to start. Jon Ablett, one of the curators at the mollusc section at London’s Natural History Museum, helps me out and picks a cabinet. He swings open the doors, revealing two rows of drawers with brass name-plate holders on each one. Carefully, I slide out a drawer and find it stuffed full of shells, sealed inside small clear plastic bags and nestled inside open card trays that look like giant matchboxes. Jon rummages through the boxes, pulls one out and puts it on a table top in front of me.

  There are two spiralling snail shells, a few centimetres tall, cream-coloured with a brown stripe coiled around them. With them are a few bits of paper covered in minuscule, neat handwriting. Jon explains that no notes are ever thrown away; even when experts re-identify a specimen as a different species they simply add their notes to the paper trail of ideas and discoveries.

  A tiny square of yellowing paper falls out onto the table with the letters MC written in fading ink. ‘That’s how we know this was one of Cuming’s,’ Jon tells me. The MC stands for Museum Cuming, the name he gave to his gigantic shell collection.

  After he died, the British Museum eventually agreed to buy Cuming’s shells for the same £6,000 he originally asked for. A story has often been told of the day when his shells were eventually brought to the museum. The weather was blustery, so the story goes, when John Gray’s wife carried tray after tray of shells across a courtyard. As she went, the air around her was filled not only with a swirl of autumnal leaves but with hundreds of paper labels from the shells, mixing them up and whisking away the names, collecting locations and all scientific value from his shells. However, investigations by Peter Dance for his book A History of Shell Collecting revealed these tales to be completely made up. It wasn’t Mrs Gray who fetched the shells, and the labels didn’t get mixed up. Perhaps people spread these rumours to try to fuel antipathy towards Cuming and his shells.

  Back in the museum, Jon and I open up more cabinets and drawers, and we keep finding more MC shells. Some of them have reference numbers that identify each individual shell in the museum’s enormous catalogue; in the past this was a handwritten ledger, which the curators are now working their way through and digitising. Normally, when new specimens arrive at the museum they are logged in with a reference number, but that didn’t happen with Cuming’s shells because there were simply too many of them. Instead they were distributed, species by species, through the rest of the museum’s mollusc collection. Only when someone takes out one of his shells, studies it, then writes and publishes something about it is it given a number. There are still masses of unnumbered shells that haven’t yet made it into print.

  ‘People are still identifying new species from Cuming’s shells,’ says Jon. Of those that have been identified, many bear his name, including Cuming’s Cowrie, Cuming’s Scallop and Cuming’s Spondylus. He has all sorts of other animals also named after him, including a starfish, a gecko, a beetle and a tree-climbing rodent from the Philippines called a cloud rat.

  I must admit that I had expected Cuming’s shells to be all kept together in one place, but actually I prefer that they’ve been split up and absorbed into this living, working collection. There are approximately nine million shells in the Natural History Museum – this is one of the biggest mollusc collections in the world – but there’s no hiding the fact that nobody really knows how many shells they have. Thousands more are added each year, and Jon and his colleagues have to keep finding more space to squeeze them all in.

  The main use of the museum’s shell collection is to study the diversity and evolutionary relationships of the immense mollusc lineage. Together these specimens form reference points in time and space that people can keep coming back to in the future, to ask questions no one has thought of asking yet and to answer them in ways that haven’t been invented.

  It’s easy to think of museums as dusty places, frozen in time, but they are constantly changing and embracing new techniques and technologies. Most of the Natural History Museum’s molluscs are empty shells, because that was the easiest way of collecting them, and in the past there was no way of extracting genetic information from them. But recent advances in DNA amplification mean that even minute scraps of dried mollusc meat stuck inside a shell can now be used to sequence the animal’s genome.

  Other unexpected and powerful insights come from whole specimens kept in alcohol. Jon tells me he recently had a visit from researcher Justin Gerlach who came to study the preserved remains of a snail species from Tahiti that went extinct in the wild decades ago. A few living Partula snails were taken into captivity for a breeding programme that it was hoped would save them from total extinction, but it’s not going well; there are only 15 snails of this particular species left, and even those are now dying. By dissecting the historic specimens from the wild it’s hoped researchers can identify their final meal and work out if the captive-breeding efforts are failing because the snails are being fed the wrong food.

  It’s not just scientists who use the collection. The mollusc department welcomes in all sorts of people: artists, designers and engineers all come through to the back rooms of the museum to learn about and seek inspiration from the shape and form, architecture and beauty of these many millions of spirals.

  Art historians also visit the department to examine an extraordinary series of shell books. Lined up along one shelf in the mollusc section’s library are 20 huge volumes, their titles and contents embossed in gold on the spines: ‘Vol. 1. Conus, Pleurotoma, Crassatella, Phorus, Pectunculus …’, ‘Vol. 2. Corbula, Arca, Triton …’ all the way through to ‘Vol. 20. Solemya, Mya, Clausilia, Cylindrella …’. They aren’t in alphabetical (or even taxonomic) order, but that would probably have been asking too much for a project that took more than 30 years to complete. I pull down volume three, ‘Murex, Cyprae, Haliotis …’ and carefully open the pages.

  The beautiful colour illustrations are vivid and lifelike, almost as if the book were filled with real shells. The polished humps of cowries seem to perch on the page; an abalone bigger than my hand shimmers with many colours. This is the Conchologia Iconica by Lovell Augustus Reeve, one of Cuming’s closest friends and associates. He began the book in 1843 and continued until his death in 1865, at which point George Brettingham Sowerby II took over, finishing the work in 1878. There are other splendid copies of the book in museums and libraries around the world and you can browse a digitised version online at the Biodiversity Heritage Library.

  The Iconica series illustrates around 27,0
00 shells. Between the illustrations are written descriptions of each species, including many delightful common names. There’s a Greenish Cowrie and Yellowish Terebra, a Differently-bristled Bulimus and a Somewhat-distorted Triton; I spot a Grinning Cockle, an Ambiguous Murex, a Flea-bitten Cone, a Lovely Cone, a Melancholy Cone, and I can’t help feeling a bit sorry for the Dismal Limpet.

  The bulk of the shells that Reeve and Sowerby used for their drawings and descriptions came from Cuming’s collection. The books include details about who found each particular shell and where. Repeated throughout, more often than any other name, is ‘Mr Cuming’.

  When Reeve started this great work, the Sowerbys had already begun to publish a five-volume shell guide, Thesaurus Conchylorium. I glance through a copy of this in the library and see why the Iconica was set apart as something quite different. The Thesaurus is illustrated with etchings, fine black lines painted in colour by hand. They are quite beautiful but give more of a stylised view of the shell rather than a realistic impression. Most of these drawings are also much smaller than the shells themselves. In contrast the Iconica illustrations are all life-size or bigger, which is one reason why it runs to 20 volumes (Reeve also wanted to include every known species at the time). And these are lithographs, a technique that allows for more subtle lines and shading. Until the invention of colour photography, this was probably the world’s finest and most accurate book of shells.

  The pictures in Iconica are so detailed and accurate it’s possible to search through the museum’s cabinets and find the actual, individual shell from the collection that Reeve or Sowerby drew. And I can’t resist going back for one last look at Cuming’s shells.