Mo. Rev. Stat. § 96.250

Said board shall be nonpartisan and nonsectarian and the members and officers thereof shall receive no compensation as such. Said board shall consist of the mayor of such cities, who shall be ex officio a member thereof, and six other members, men or women, who shall be appointed by the mayor and the common council of such cities, who shall hold office, two for one year, two for two years, and two for three years, whose term of office shall be designated by the mayor. Whenever the term of office of any member so appointed expires, the appointment of his successor shall be for three years. All such appointments shall date from the first of June following their appointment. Vacancies from any causes shall be filled in like manner as original appointment. The mayor may, for misconduct or neglect of duty, remove any members appointed by him in the manner required for removal of officers of such cities.