It is not yet clear exactly what the structure of women's professional tennis will be next year, in the wake of the Women's Tennis Association's decision not to renew its contract with Virginia Slims for the circuit of tournaments that formed the backbone of the winter tour the past eight years.

There has never been a women's pro tour without the cigarette company. It was the original sponsor of the modern women's game, there at the beginning in September 1970, when eight women rebelled against an 8-to-1 ratio in prize money in favor of men at mixed tournaments.

Led by Gladys Heldman, the publisher of World Tennis Magazine, they declared their independence and set up a renegade $7,500 tournament in Houston, in defiance of the then male-chauvinistic U.S. Lawn Tennis Association.

Its succedd paved the way for the first Slims Circuit in 1971. With Heldman orchestrating, Slims footing the bills, and Billie Jean King talking and playing up a storm, women's tennis was dragged into the American consciousness.

In the ensuring years the tour grew beyond aby of its founders' fondest dreams. But next year, for the first time, there will be no January-through-March Slims Circuit.

Instead of 11 tournaments with uniform prize money and 32-women fields leading to a final playoff for the top eight performers, there apparently will be independent tournaments of varying size, format and prize money, with individual sponsors.

The circuit concept, with symmetrical tournaments linked together by points and leading up to a grand finale, apparently is out. Variety, with a different ball game in every town every week, seems to be in.

Dissimilar tournaments still could be loosely connected with an umbrella point system, as has been the case in men's tennis for several years. The Colgate International Series, the Women's equivalent of the men's Grand Prix, already links fall tournament, leading to bonus awards and an eight-Woman championship, and it problably will be extended year-round.

There is also a movement, spear-headed by king, to include World Team Tennis matches in the Colgate Series, since most of the world's top women compete in WTT. But this is just one of numerous details to be worked out following the WTA's landmark decision to part company with Slims, which may yet encounter opposition from the rank-and-file of women players.

Money apparently was not an issue. Slims had offered to up the ante next to $1.72 million for three months: 11 tournaments, each with $120,000 purses, leading to a $400,000 playoff.

The difference, according to Jerry Diamond, the WTA's strong-willed executive director, was philosophical, concerning the shape and structure on the circuit.

Some influential women players wanted to scrap iniformity and introduce "special events" - including at least two $200,000, 16-woman tournaments - into the Slims season. Ellen Merio, brand manager fo Virginia Slims and also a strong personality, would not go along.

It has not been fully explained what led to the final brakdown in negotiations that had been going on for five monts between the WTA and Slims, which has spent between $8 and $10 million on women's tournaments since 1970.

A personality clash between Diamond and Merio may be one factor. King's determination that women's tennis needs "a kick in the pants, something new and different to create excitement and stimulate growth in new directions" undoubtedly is another.

The WTA believes sponsors are ready to beat a path to its door. Diamond said he "firmed up three or four solid offers" for tounaments Friday, within hours of the announcement that the Slims contract wouldn't be renewed.

"It won't be easy. The women are going to have to deliver a good product, as they always have, but O imagine we'll have more than $2 million in prize money next winter," King said.

"We're going to have to pull up our socks and work harder than ever before to keep growing."

The women players must remember that. Virginia Slims enjoyed a unique position among tennis sponsor because it cultivated organizational innovatins and continuity that should not be lost because of its departure.

In addition to putting up prize and promotional money, the company took an active role in organizing and presenting tournaments with a slic, professional image. In so doing, it made its brand name synonymous with the events. To tennis enthusiasts, "Virginia Slims" meant not a cigarette, but women's tennis.

From a marketing standpoint, this was a great accomplishment, and not withour irony. Critics often pointed out that it was a peculiar marriage between a healthful game and a product the surgeon general had determined was detrimental to the national health.

What the women players should remember, and not let lapse, is the all-encompassing approach Slims took. It engaged couturier Ted Tinling to design attractive fashions, hired an able tour director and staff to assure that tournaments ran smoothly and fairly, and saw to it that players were coached o show biz aspects, schooled in their obligations to the public and press.

This was not done altruistically. Slims also reaped rich rewards in publicity from its association with women's tennis. It traded on the fact that it was the cigarette of women's lib. Its slogan - "You've come along way, baby" - became that of the women players, too, and they were constantly interwined.

The result was that the efficiently organized and lavishly promoted Slims Circuit became the most recognizable, comprehensible and professional entity in tennis.

"Women's tennis looks really healthy in comparison to two years ago. There is more depth than ever before, with young players like Tracy Austin, Pam Shriver and Anne Smith coming along, Evonne Goolagong and Chris Evert back, Martina Navratilova playing better, and the old ladies like me still around," says King, who says she was saddened that Slims would not compromise.

"It's a time of great opportunity. That's why we wanted to inject some new sparkle, to really get it moving. Unfortunately, Slims wanted to keep the status quo and wouldn't budge an inch, so we had to go forward without them."