A federal judge ruled improperly, using evidence never presented in court, in the case of nine South Ardmore students who alleged racial bias in school redistricting, their attorney said in a brief filed Monday.

In the appeal, filed with the U.S. Court of Appeals for the Third Circuit, David G.C. Arnold argues that District Judge Michael M. Baylson should not have sided with the school district based on the case it presented at trial.

After nine days of testimony, Baylson ruled in June that the school system used race as a factor in redrawing school lines, but not illegally.

"Because the district maintained that it never used race, it cannot simultaneously argue that its use of race was somehow justified," the students' spokesman, James Herbert, said by e-mail Tuesday. "The court improperly provided a defense to the defendants on issues they never proved - or even argued."

Lower Merion officials said Tuesday that they would continue to defend their redistricting plan in court, but declined to comment specifically on any issues raised in the students' appeal. They have 30 days to file a response with the appellate court.

Lower Merion's 2009 redistricting plan reassigned students between its two high schools to balance their populations. As a result, students in an area of South Ardmore lost their traditional choice to attend nearby Lower Merion High School and were assigned to Harriton High School, a five-mile bus ride away.

The students - whose identities have been kept anonymous in case filings - argued that the decision was made because they were black. The district maintained that race was only one of many factors used, including travel time and geography.

Baylson cited a portion of the Equal Protection Clause in his June 25 ruling that permits governmental entities to make race-based decisions if they can prove that doing so addresses a compelling state interest and that their actions are narrowly tailored to achieve that well-defined goal.

Contact staff writer Jeremy Roebuck at 610-313-8212 or jroebuck@phillynews.com.