Forest Preserve District of Cook County, Illinois
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Nature Bulletin No. 74   July 13, 1946
Forest Preserve District of Cook County
Clayton F. Smith, President
Roberts Mann, Superintendent of Conservation

In the sandy bottom of a clean lake or stream you may see a shallow furrow that twists and turns. At the end is something like a small moss- covered rock. Pick it up. If there is a squirt of water, a pink tongue is quickly drawn in, and the two halves clamp tight together, you have a mussel.

"Clamming" once made up a considerable part of the fishing industry in the streams of the Mississippi valley. Pearl buttons, knife handles, buckles and novelties were made from their shells. Their soft bodies yielded pearly slugs used in lavalieres and cheap jewelry. Very rarely a real pearl was found. Some of the finest pearls have come from certain tributaries of the Ohio and Tennessee Rivers where conditions seem ideal for luster and translucence. One pearl, taken from the Wabash River near Terre Haute in 1927, sold for $50,000.

Only a dozen or more of the several dozen species of mussels in the Mississippi valley have the thick white shells used for making buttons. The best of them have these colorful names: mucket, pocketbook, washboard, three-ridge, pimpleback, elephant ear, buckhorn, niggerhead and maple leaf. The "yellow sand shell" is the best for buckles and large ornaments.

Watch a mussel, lying on its side in shallow water, get up on edge and crawl. The hinged shell opens a half-inch or so and out comes the "foot". Shaped like a human tongue, this foot can be extended into a long finger-like tip. This tip is worked into the sand for 2 or 3 inches, then the foot contracts, raising the mussel on edge and moving it forward.

Mussels grow very slowly. Their ages can be told by growth rings on the shell. Most commercial varieties get to be 15 or more years old and the three-ridges may live to 35 or 40 years.

Most mussels shed eggs or partially developed young to carry on a free existence, but the young of several species pass through a parasitic stage attached to the gills or skin of fish. The young "yellow sand shell" will live only on gar fish.

There are two sexes but the difference is important only to another clam.

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