Black students returned to classes in Senatobia, Miss., ending a 14-day boycott, and a black leader says the heat now will be on white firms. The boycott began Feb. 17 after the school board hired a white assistant superintendent. Blacks said the board--three whites and two blacks--reneged on a pledge to hire a black. White school board members said they only promised to hire a black if a qualified candidate could be found. The boycott ended after the board agreed to hire a black administrative assistant and a black counselor.