Mo. Rev. Stat. § 86.517
The city treasurer, counselor, city clerk and comptroller, or such other officers exercising such functions while holding such office, and the chief officer of the police department, two delegates at large from the police department to be selected by the members thereof annually, whose term of office shall be one year and two delegates from the pensioned list, if any, to be selected by such retired or pensioned members on the thirtieth day of June of each year, who shall hold office for one year, shall constitute and be a board by the name of "The Board of Trustees of the Policemen's Pension Fund". The said board shall make all needful rules and regulations for its government in the discharge of its duties. The board shall select from their members a president and secretary and shall establish their own order of business.
Effective dates prior to 1940 may not be the actual effective date. See FAQ 'When do laws become effective?'
§ 86.517, RSMo
RSMo 1939 § 9478