The race is officially on for Cambridge City Council and School Committee seats, with the pool of council contenders up significantly from two years ago, while the number seeking school committee slots has dropped by nearly half.

By the 5 p.m. deadline Wednesday, 22 candidates had filed papers for the council election--six more than in the 1983 election. Nine have joined the race for the seven-member school board, down from the 16 contenders two years ago.

While all nine city council incumbent's will seek reelection to the council, two veteran school committee members have opted out of this fall's race.

In a surprise move this week, 12-year veteran of the school committee Glenn S Koocher '71 announced that he would not seek another term in office.

Koocher, who was instrumental in the district-wide school desegregation of the late 70's, said yesterday that serving on the committee "consumes an enormous amount of time, and that it's time to move on to other things in my professional life."

Koocher has been an outspoken member of the committee since 1973, when at the age of 24 he became its youngest member even. The Blue Cross social worker has been active in coordinating hiring and financial aspects of the school system, and actively lobbied to oust former Superintendent William C. Lannon.

Rena Leib said she will not seek a second term on the school committee, citing her desire to spend more time with her family.

In the first surprise of the council race, three Cantabrigians have entered the contest on a slate they have called "Coalition '85." The three are Karen Swaim, the president of the Business Association of North Cambridge; Hugh A. Russell, an architect who is on the board of zoning appeals; and Geneva Malenfant, a resident of Cambridgeport, who has served on the planning board and the historical commission.

Malenfant said yesterday that her "progressive, good government" coalition is offering an alternative to the Cambridge Civic Association (CCA) and the independents who currently dominate the board.

Sometimes the heightened feelings among the two groups hasn't led to the most productive atmosphere for things to happen for the public good," said Malenfant.

CCA endorsed Councilor Alice K. Wolf, who is the only single term councilor up for reelection, said yesterday the new slate and the large candidate pool this year "will certainly liven up the election, and will probably eat into the constituencies of incumbent candidates."

Wolf said she and the other CCA incumbents are particularly concerned with the issue of development, and will continue to block proposals that would allow North Cambridge to become as built-up as Mass. Ave from Harvard to Central Square.

"Such a situation would not be compatible with safety, noise, and traffic in the area," she said.

Incumbent CCA-endorsed candidates include Councilors David E. Sullivan, Saundra Graham, and Mayor Francis H. Duehay '55. Incumbent independents include Thomas W. Danehy, Daniel C. Clinton, Alfred E. Velluci, Walter J. Sullivan, and Alfred W. LaRosa, who was elected just last month to fill the seat of the late Mayor Leonard Russell.

School Committee Criticized