As early as 1847, a certain William Traill, M.D., junior colleague of a certain Dr. Little, noted, in the launch issue of what became popularly known as Logan's Journal, a "remarkable paucity of the larger and more gaily coloured shells" despite the presence of an "extensive and varied" coast around Singapore with "numerous sheltered bays and islands, with large tracts of level sand, and in other places, shelving rocks clothed in part with a variety of Algae."
Seeking a cause to this effect, he suggested this scarcity arose as "the poorer Malays and Chinese use most kinds of shell fish as food, and search the shores for them with such diligence, that they have caused a dearth of such as are common in less frequented parts of the coast." Supporting this hypothesis was Dr Traill's observation that large shells, including those of the "genera Hippopus, Tridacna, Spondylus and Chama", were abundant at little-inhabited islands 30-40 miles south of Singapore. The latter two were "much used as food by the natives", who also consumed in numbers "Arca granosa," "Corbicula regis," "Cerithium lineolatum" and "Voluta melo".
Dr Traill, who otherwise spent his time examining exhumed specimens of Homo sapiens to ascertain the origins of their demise, did not neglect to explore the shores at low water, going as far as "Pedro Branca" and reporting sightings of "the Voluta undulata, the inhabitant of which is spotted with blotches of bright red on a dark ground, and readily catches the eye, at a distance of some yards, as it moves like a huge snail through the coral foliage". Also noted were "Voluta melo" and "an abundance of a small species of Meleagrina of Mother of Pearl Oyster". Cowries, especially Cypraea olivacea were common under flat stones. Following the norm of an earlier time, Dr Traill ranked Echini among the Mollusca and found "a considerable number" on coral banks, though he neglected to add much further detail.
Dr Traill's accompanying "Catalogue of the Shells of Singapore" was similarly tardy. More species were enumerated than identified; for instance, he named four species of Trochus "and nine others". "Cassis glauca" made it into the checklist, along with four species of "Buccinum", 20 cowries, two olive snails, six cones, seven strombids, 15 species of "Natica" (he only named N. mamilla), a single "Solarium" and tantalisingly, a creature by the name of Nautilus pompilius.
More recent surveys of the island's shelly fauna reveal less dire numbers but a greater sense of peril that what little is known about the majority of creatures in the list might be as much as could be learnt before they succumb to the acid flask of hotter seas. Traill's "extensive and varied" shores are also much reduced; the mangroves, mudflats and cliffs that once ringed the island have surrendered to a civilisation with little tolerance for clutter and even less patience with habitats with nothing to offer but a wealth of returns none can cash in.
Coral reefs, for all their diversity of niches, provide little room for soft creatures in large shells. Benthic molluscs of a charismatic bent and bulk appear to thrive more in flats of sand and mud through which they can glide with little hindrance. With scant aufwuchs, these shoals are inhospitable to grazers; to thrive in these gentle slopes, one must reach out to pluck morsels in midwater or rasp at fellow burrowers who have done the dirty job of sucking in the goodness between the grains. The snails that live in soft bottoms are hence little like those that browse in gardens; many have turned to a life of bloodlust, pursuing sea cucumbers, sand dollars, sea stars, polychaetes and cnidarians, as well as cousins they can overtake, before drilling their way in or simply swallowing their prey whole.
Moon snails, in essence a foot of slime too large for the nipple of a shell, move like moles in slow motion as they scour the substrate of hidden bivalves, gastropods and dim-witted crustaceans. The adults can be difficult to spot under a coat of silt or easily mistaken for awkward slugs by their consummate mantle, but signs of their presence are evident in collars of sand and organic cement that disintegrate when they release a brood of veligers. Olive shells, too, leave tell-tale traces of submarine hunting expeditions that end in an embrace of fatal ravishment.
The predatory volutes, common in the nodes of seagrass meadows, similarly chase down and overpower their prey with a fleshy hug. In turn, they draw the attention of men who make their bodies into substantial meals and use their capacious shells as curios or handy containers. Bailer shells were scarce, however, at the Lost Coast, which harboured little seagrass on a broad bay of sand that had formed before an artificial foreshore of scrubland and swampy fields. The grains, firm yet fine enough to form ripples in the wake of receding waves, were instead a haven for sand dollars, which littered the seabed with living bodies of velvet underground and the pale remains of empty coins.
Having imbibed the nectar of soft deposits, this spineless horde is a reservoir of bounty for an army of snails who cruise the shoal in hard and heavy hats that probably help to pin down the urchins while the snails bore holes through their tests. A massive species resembling a classical war helmet has not been recorded in local waters, but smaller cassids teem in this zone of intertidal contention. The greyish-brown shells, globose with a minuscule spire, the slightest of ridges and a lip of uncouth spines, houses a body of cream and caramel with chocolate trimmings. Pin-hole eyes peek from the base of feelers that probe their surroundings for signs of echinoid life.
Tun snails have been found here, too, indicating an abundance of holothurians in the sediment. Another reputed foe of spiny skins is Ficus, whose shells reminded some of the flesh of a flowerless tree. In living specimens, the blotchy lobes extend to partially envelope the whorls like the sepals of a glabrous fruit. A modest head leads the way under a tapered siphonal canal, from which a long trunk also protrudes. The animals lack an operculum and seem reluctant to retreat into the safety of their coils when poked, and it is thought that the thinner portions of the mantle serve as sacrificial parts to placate fiercer hunters. Turrids also bear pointy front ends, but the rear half of this family forms a slender spire with prominent ribs, grooves or spines. Predators with poorly defined diets, though worms are thought to be their primary prey, these snails are cousins of the cone shells and share the armament of a spear tipped with paralysing force.
With luck, the Lost Coast might also reveal a few harps, robust snails that have learnt to snare crabs and shrimps using a net of mucus. Like Ficus, harpids are wont to shed dispensable bits, a strategy that probably appeases most predators save the lovers of hard shells. Another prize for collectors is the sundial, which devours sea anemones, zoanthids and coral with impunity, thanks to a reinforced mouth.
Amid a scene of interphyla carnage, the Lost Coast offers a refuge for another host of small shell fauna, the choice quarry of naticids and a source of visual delight in their diversity of morphs and extreme reactions to disturbance. No more than half-an-inch in diamater, button snails are the benthic kin of rock-scaling top shells, peas of a massive pod and ubiquitous components of undredged shores, where they vie with the pebbles in number and support in life the appetites of larger gastropods and thereafter, the naked torsos of tiny hermits.
Despite their size, beady eyes still beckon from stalks and the animals are eaten in the Philippines, where an aromatic thorn is used to pry the beast from its shell. The lenticular coils hides a surprisingly long foot, which is employed to great effect when danger passes to vault the snail to safety. Another curious flight response is the forming of rafts that drift before individuals drop back to the bottom. For these colourful knobs of pearly lustre, such a repertoire of tactics is probably a necessity in habitats replete with hunters who would otherwise decimate the last populations of a little thing with no appeal and even less clout to the builders of bare, barren beaches.
Comments