Seashells by the Seashore
Throughout the summer
season, scores of people travel to the shore. Often in the mornings, you
can see folks out combing the beaches to see what the tide left behind.
Seashells are admired by many and often collected by children. These
natural wonders, strewn along beaches like jewels from the sea, are created
by snails, clams, scallops, and other marine mollusks. For a very
long period of human history however, these shells were far more than the
evacuated homes of sea creatures and objects of childhood fascination.
They held a position of value, being used as money, medicine, precious
ornaments and even used in art.
There was a time when shells were of the utmost importance. Cowry shells were used as money, ornaments and charms. To prevent sterility, women of Pompeii wore cowry shells. We have even found that cowry shells were worn by Cro-Magnon man, as indicated by ornaments found in their caves. Archeological excavations of Saxon graves in Germany, as well as pit dwellers of prehistoric England and pre-dynastic Egypt have revealed theuse of the shells. Prehistoric cemeteries in the northern slopes of the Caucasus mountains near the Caspian Sea have revealed large numbers of shells. And as late as the 19th century, cowries were used for money in Uganda and other parts of Africa.
It has also been discovered that Cowry shells played an important role in burial rituals in ancient China. When the emperor of China was buried in those early times, his mouth was stuffed with nine cowries! Feudal lords were buried with seven shells, high officers five, and ordinary officers three. Common people generally had their mouths stuffed only with rice. But if a commoner had some wealth, the last molar of each side of his mouth was supported by a small money cowry. This was to ensure that the dead had plenty to eat and spend in the afterlife.
The shells of some snails were also important to our ancestors. In the16th Century, natives of Central America poured Purpura Patula snails into cauldrons and crushed them. The mashed snails shells would ooze a purple dye which was used to color cloth. By 1648, the natives had started exporting this dye to Spain. There was such a high demand for the dye, the natives were forced to find ways to maintain their supply while not endangering the population of snails. By imposing conservation measures, they instead learned to pluck a snail off the rocks, gently blow into its shell and collect the dye that trickled out. The snail was then returned to the rocks unharmed.
Other cultures dyed cloth with mollusk juice. When Antony and Cleopatra sailed in the battle of Actium, their sails were colored "tyrian purple." This famous color was derived from shellfish in the Murex family. The shells were used for this purpose over three and a half thousand years ago on the island of Crete and possibly as far back as Neolithic Man.
In Babylon, idols were clothed in tyrian purple cloth. Rome's emperor Nero was the only person in the empire allowed to wear cloth of that color. But dying clothes purple was costly. It took 300 pounds of the liquid dye to color 50 pounds of wool! The dye was very long-lasting. Mummy wrappings in some museums, dyed with the purple dye, still show their colors after thousands of years!
Mollusks provided rare finery for the wealthy in the ancient Mediterranean.Tufts of golden silk thread were plucked from the Noble Pen shell. They were used to manufacture gloves, stockings, caps, and other specialty clothing. The two foot long threads, called byssus, were fine and strong with a deep bronze gold coloring. Their real use was to help anchor the pen shell face down on the sea bottom against currents and underwater swells. It's thought that the Golden Fleece, sought by the legendary Greek hero Jason, was woven from pen shell threads.
Mollusks can be found in an amazing range of environments. Clams and snails can be found living on mountains, in lakes and ponds, marshes, bays and estuaries, along sandy seashores, floating on the sea surface and living at the bottom of the sea, near hot springs. Snails can be found living in high trees, in the intestines of sea puddings, and within the arms of starfish.
Seashells occur in an amazing range of shapes, colors and sizes. One of thesmallest seashells is the Pythina clam, a tiny, smooth translucent clam the size of a rice grain, that lives attached to the underside of shrimp and crayfish. At the other extreme is the largest known seashell - the giant Tridacna clam of the southwest Pacific. This monster's shell consists of two attached valves which are four foot long and weigh 500 pounds!
The largest, most common, and best known seashells are the univalves or gastropods - conchs, whelks and snails. They have one shell, which is often coiled. Single-shelled animals first appeared in the fossil record 500 million years ago. Some gastropods, such as limpets and abalone have flat saucer-like shells. Snails are the only mollusks to have the distinction of colonizing land as well as freshwater and marine habitats. The Aztecs of ancient Mexico depicted their rain god, Tlaloc, rising from a conch shell. The Greek god Triton, one of Neptune's trumpeters, was depicted with a large conch shell that he used to summon river deities around their king.
Mollusks can make shells because their blood is rich in liquid calcium. They concentrate the calcium in areas and separate it from the blood, forming calcium carbonate crystals. They crystals are deposited in layers of varying size, shape and orientation. The layered construction strengthens the entire shell. Colors in shells are created by pigments found in food. The formation of spines, grooves and ribs on shells aid in protecting the inhabitant and in some cases add strength. Production of new shell material is influenced by several factors: sexual hormones, intrinsic rhythms, diet, acidity of water and temperature of water.
You can tell a lot about the world a mollusk lives in by looking at the shape of its shell. A shell that's low and wide might indicate strong currents or many predators. A thinner, more spherical shell probably came from deep water or from areas around the north and south pole. These are places that are poor in calcium, unlike rich tropical waters. On hard seafloors, crawling gastropods have coiled shells or flat, saucer-like shell cases that allow them to retreat into the shell when in danger.
The value that many folks these days attribute to shells is that of food. shellfish such as clams, oysters, scallops and mussels are popular on menus all over the world. This has its roots in the earliest times in human civilization. Remains from ancient kitchen contain large amounts of oyster, clams and univalve shells. Sites such as this can be found all along the North American coasts, left by ancient Indians.
In ancient Greece and Rome, shellfish were main dishes on menus, as they still are to this day. Early American colonists learnt that maritime Indians sustained themselves through harsh winters by eating oysters when land crops failed.
Shellfish have even played a role in ancient medicine. The heart-shaped Cockle Clam was believed to be good for the heart. Some mollusks, especially the oyster have been, and still are to this day, regarded as aphrodisiacs. Pearls ground to a powder and dispensed with herbs were believed to cure stomach ailments. Snails were once used to treat bad colds and consumption.
Copyright © 2001 Kathy A. Miles and Charles F. Peters II