The count of auxiliary ballots goes on at the Central Square Senior Center, with the determination of winners in City Council and School Committee races likely, but not certain, by the end of the day.

The Election Commission began the day at 9 a.m. with the eight precincts completed Wednesday representing 1,625 of the total 3,580 council ballots. (The total had been given as 3,590.) By 12:30 p.m., the commission had made it through another eight precincts, leaving 17 to go with a total of 980 ballots. On the School Committee side, of 1,047 total auxiliary ballots, there remained 369 to look through.

The crowd at the Senior Center had dwindled, although incumbent councillors Larry Ward, Sam Seidel and David Maher and School Committee member Patty Nolan were among the waiters, as were council challengers Tom Stohlmayer and Minka vanBeuzekom.

The process is painstaking: A ballot is placed on the long table at which election officials sit; one official lays a ruler on the ballot horizontally and drags it down slowly, calling out the name of a candidate and his or her ranking as it appears above the ruler’s edge. Another commissioner tots up and records the results.

Marjorie Decker, the councillor with a write-in campaign compelled by the missing of an election filing deadline, had as many as 1,328 votes for No. 1 — the Election Commission estimate based on a preliminary look at auxiliary ballots — or as few as 1,280 based on adjudication of the ballots through 12:30 p.m. She may still be in range for winning back her council seat.

The count was occasionally made easier by obvious protest votes. One ballot had “Mickey Mouse” as a write in — in fact, as every write-in position, and ranked accordingly top to bottom in an attractive slope of colored-in vote ovals.

Update: The buzz around the Senior Center as of 4:15 p.m. is that the count is expected to end this evening. But asked whether it might wrap up between 6 and 7 p.m., the commission’s executive director, Marsha Weinerman, would say only, “I hope so.”