By late afternoon, the work is mostly done. The watermen have unloaded the day's catch and closed up Nancy's Place, their gathering spot on Main street.

The black women, their picking finsihed, are on the way home from the processing plants on the waterfront. The big trucks are loaded and heading for the seafood markets of Baltimore, Philadelphia and points to the north.

The cycle is complete. Another day in the timeless ritual of the crab and the bay is over.

For generations the crab has been the Chesapeake Bay's most familiar symbol. It is ironic that so grand a natural phenomena is represented by so ugly an unprepossessing a creature, but the beast has provided a livelihood, defined a social structure and been the source of much of the Chesapeake's rich tradition.

The cycles, commerce and history, of he Chesapeake all can be seen through the life of the crustacean that symbolizes it. To understand the story of the crab, the waterman who harvest it, the pickers who take it apart, the businessmen who process and distribute it, is in a sense to know the bay.

In Crisfield on the lower Eastern Shore, all the parts come together to form a whole. There are tourists who come to take the ferry to Tangier and Smith Islands, but the main business is crabs.

An eternal rhythm prevails here defying the cyclical uncertainties of the crab. This spring, Virginia marine biologists forcast a crab far below last year's bay-wide catch of 62 million pounds, but Maryland officials disagreed. Chesapeake waterman just went about their business.

To the 9,000 full-time watermen who work the bay, an ample supply is only one factor in the equation of making a living. Demand, for hardshell crabs especially, is down this year, a fact often blamed on the economy. So is the summer supply of softshell crabs, a phenomenon blamed by at least one watermen here on Jimmy Carter.

But whatever the supply and demand, the Chesapeake Bay continues to sustain this town built over oyster shells on the Eastern Shore.

Seen from the water, she is a dowager past her prime, shrunken in size, her shopping district half shut down. From the water though, Crisfield bustles with commercial life. The crab houses line both sides of Somer's Cove, the harbor's main street. What begins before dawn on the water ends here, at land's end. The waterman

William D. Dize was a little late getting started. His brother-in-law, Elmer F. Evans Jr., was already at work culling softshell crabs from his floats, and all the other workboats were gone when Diez and sons "Smitty 10, and Martin, 4, boarded the Miss Sally. It was not yet 5 a.m.

The 40-foot workboat moved quickly from its mooring on Smith Island through a narrow channel and into Tangier Sound. The CB radio crackled its own version of the Today Show.

"Quite a little crab out here," a voice said.

"I've seen' more than I've been seein,'" came the reply.

Bill Dize had 150 pots to pull, all laid out in six rows of 25 each and distinguished by red markers. Normally he had 100 more, he said, "but it ain't worth it right now. The price just ain't that good."

Male crabs, the "jummies" that are sold for the steamed-crabs-and-beer crowd, were bringing only $10 a bushel down from $17 two weeks ago.

"I guess you gonna bait crabs as long as you live, ain't ye?" the CB radio voice said as the sun rose over Chesapeake Bay.

Bill Dize almost always had, ever since his father's contracts had forced him to retire early and his son, at age 13, to quit school and follow the water.

It is a path taken by many on the water. The best education for a waterman, they will say, is not to be found in the classroom. But often they want more for the sons, the way Bill Dize wants more for Smitty.

"I hollar at him for his own good," Bill Dize said. "I make it as hard as possible when he goes out with me so he'll think it over before he quits school."

An advanced degree to a waterman often takes the form of a Coast Guard charter boat captain's license. It offers a second income and the captain is still the boss. "Billy Dize, Licensed Captain," the printed card says, "Fishing parties our specialty."

For a while, Dize left the water and spent three years in Washington selling seafood on the Maine Avenue waterfront. He has found memories of nights spent on the 14th Street strip and not so fond ones of tear gas on the Mall. Washington "was all right," he said, "but it wasn't as good as on the water."

Some days, like this one, Dize dosen't have to make it hard for his son or himself, it just happens. The hydraulic winch that helped him hoist the rectangular metal pots fell, and the boats engine twice overheated.After a while, Dize had to pull pots the old way, by hand.

Fifteen of the pots were badly bent, a condition Dize blamed on the clam dredgers who share the same waters. Before double-digit inflation, he said, "you'd throw the old pots away. Now everything's so expensive, you keep 'em as long as you can."

From each pot, Dize dumped the contents into a worn rubber tray, and tossed the "jimmies" into a wooden basket and the "sooks" (female crabs) into a big barrel bound for the crab picking plant. Along with the crabs came an occasional flounder, bluefish, toad fish and an abundance of sea nettles, also known as jellyfish, which sting.

"You know when you go to the dentist and he gives you a needle? That's just the way my arm feels right now," Dize reported. It was 7:30 a.m.

At the age of 31, Dize's face is weathered, his body burly and bulky. Only his longish blonde hair and his "Play Boy" tattoo gave him away as a child of the 60s."I'll tell you," he said, "the way I feel sometimes, I ain't very young."

The young on board were William Smith Dize Jr., "Smitty," who helps steer the boat and pack the baskets, and Martin, whose mind was on a milkshake most of the time.

"Well, it's getting hot now, my sideburns are sweating," a voice over the CB said at 9:20 a.m. "it's getting hotter than fire," Bill Dize agreed.

By 10:30, three 50-pound boxes of crab bait were empty and Dize cleaned up the boat and himself and headed for Crisfield.

Inside Somers Cove, Dize pulled the boat alongside a parking area where refrigerated trucks waited to take the hardshell crabs to Baltimore and Philadelphia. Dize's catch was 14 bushels "and a piece." The men on shore counted out just under $150 in bills.

Dize brought the Miss Sally around the city dock to the Metompkin Bay Oyster Co., where owner I. T. Todd was waiting to weigh and record his sooks. A mechanical device lifted the two barrels, which had a combined gross weight of 280 pounds. The net weight would be computed and Dize's payment made at the end of the week. If last week's price held, Dize would receive 17-1/2 cents a pound, 30 percent more than last year.

He would need it. Miss Sally swallowed $26 worth of fuel for one day's work, and the winch would cost $150 to repair. The Picker

"Your crab picker is a dexterity worker," explained Mace N. Foxwell, manager of the Maryland employment office here. "If you're all thumbs, you might as well forget about making a living as a picker."

There are about 400 crab pickers in Crisfield, most of them women and most of them black. At $1.15 a pound a good picker can gross $300 a week, but it is seasonal work, and the people who do it constitute a kind of underclass of the Bay.

In the winter, they collect unemployment as the oyster shucking men do, during their off season. Automaters have tried to perfect a crab-picking machine. All they have to show for their efforts is an expensive contraption that noisily shakes 100 lbs of crab meat an hour but cannot distinguish between succulent lump meat and the rest of the product. The packagers sell it as "Maryland Deluxe Crab Meat," but the women aren't worried. Not even machines, they know, can replace the pickers.

The crabs bought at dockside are steamed -- 1,200 pounds in 12 minutes -- in a huge cylindrical pot, cooled overnight and then brought in a wheelbarrow to the room where Metompkin's 35 or so crab pickers sit four to a table.

The fastest crab picker in Crisfield works here. She is Mary Elizabeth Ames, also known as Miss Liz.

"I love it, I just love it," said Miss Liz, who is 55. "I make a decent, honest living. I just come in and be quiet and keep my mind on what I'm doing. Most of the times, I sing hymns . . . 'How Great Thou Art,' 'Trust in God.' I trust in him. And the crabs, they follow."

It is a simple routine. First, she pulls off the two large claws. Then, crab in her left hand, knife in her right, she goes to work. Off comes the crab back. The knife scrapes the insides, first the eggs, then the lungs or what the pickers call "dead man's fingers." The other claws and backfin are discarded and, finally, the lump and little meat chunks are extracted from the core.

She quickly fills the six cans in front of her, and takes them to another room to be weighed. Between 7 a.m. and 3:30 p.m. one day last week, she picked 55 pounds, for a gross of $63.25 Nobody else had come close.

Ames quit school in fourth grade and "picked potatoes and skinned tomatoes" to help raise her nine brothers and sisters when her mother died. At 19, she became a crab picker.

"In other words," she said, "I've just been a hard worker all my days."

The fruits of her labor include a modest, pink-shingled house on the outskirts of Crisfield, its walls filled with homilies to home and God.

Her dining room table is covered with a lace cloth, a Bible, family photos and several trophies won at the annual Labor Day Crab Derby. In 1966, she came in first in crab picking but her employer kept the trophy.

She is proud of the trophies but prouder of the children she sent to college, her daughter who teaches first grade in Salisbury and her son who is a policeman in Syracuse, N.Y.

"I did it all with the help of God and these fingers here," she said. "No help whatsoever except for Godamighty and these hands, and it all came from crab picking."

Her granddaughter tried picking and didn't like it. Her daughter was "better than I was" at it, but wanted something more. She is the last of her clan to earn a living in what is to many messy, demeaning work.But not to her.

"I'm just so happy to get up in the morning and get my clothes on and get to my job," Miss Liz said. "I love it to death. I've had regrets, even shed a few tears, but this job is pay enough for me, thank the Lord. I can't think of nothing else." The Company President

Bill Dize and Liz Ames don't know each other, but both of them know I. T. Todd. "About as square as it is round" is how Dize describes him. "About as fair as they come," said Miss Liz.

Ira Thompson Todd Jr., 62, was the last baby born on Holland Island before its residents surrendered it to the bay. Their land washing away with each storm, the islanders dismantled and moved their homes to the mainland.

I. T. Todd Sr., had been a commercial waterman, crabbing, pound netting and oystering in a two-masted bugeye below Calvert Cliffs from Cove to Cedar Point on the western shore. When the military declared his fishing grounds off limits during World War II, the senior Todd acquired an interest in an oyster shucking house. It was located on Metompkin Bay on Virginia's Eastern Shore. He kept the name but moved the business.

I. T. Jr. went to college to study accounting, but the war interfered and he returned to run the oyster business. Gradually, he bought out the other partners and expanded into crab meat and soft shells.

Like a waterman's son or a crabpicker's daughter, Casey Todd came to the processing end at an early age. He worked weekends and summers, standing on a box when he was small to pack soft shell crabs for the city markets.

Now, even though he is management, his work week is as hard as the waterman's or crab picker's. "The springtime soft shell rush is a killer," he said. "He [the peeler crab] don't stop shedding on Sunday's just because he want a vacation."

From a dozen employes, Metompkin has grown to employ 75 during the peak period in the fall, when crab picking and oyster shucking overlap.

It is among the largest of Crisfield's dozen crab meat plants. Some 16 watermen regularly bring their catch to its docks.

It's a business that lends itself to individual operation, said Todd. "You've got to have the personal touch with the crabber and so forth. They look for it. You can't operate this business by remote control."

Todd spends much of his time dickering over the phone with food brokers who set the prices and buy his product. "It's not like the stock market where you have bidding every day," I. T. said. "The A&P has paid me the same price for the past six weeks."

While the price paid for hardshell crabs fluctuates from day to day and week to week, pasteurization and freezing have brought a measure of stability to the crab meat market, "leveling out the peaks and valleys," I. T. said.

The business has been good to him. He lives in a red frame house in a nice section of town, right next to the widow of the late Maryland governor J. Millard Tawes. He has sent one son through law school and another to learn medicine, and, now, he is ready to retire "whenever it gets convenient for me."

He sent the son to law school in case the seafood business went bad, but Casey Todd, it was always understood would someday manage Metompkin.

"If I don't come in the business," Casey Todd said, "what's taken generations to build would go down the drain. When you sweat blood over something like this, you'd like to see it carried on."

The line of succession is not always so clear in the seafood business, however.

Liz Ames' progeny have distained her crabpicker's craft. Ten-year-old "Smitty Dize wants to be a baseball player. Further up the Bay in the fishing village of Rock Hall, the future for waterman George Reihl and his family suddenly has gone aground. Recently Reihl leased his work boat and went to work managing a Chestertown sandwich shop.

"Yeah, man, I'm a new honcho now," he says. "It's a lot easier."