The treasurer of the board of trustees shall be the custodian of said pension funds, and shall secure and safely keep the same, subject to the control and direction of the board, and shall keep his books and accounts concerning said funds in such manner as may be prescribed by the board, and said books and accounts shall always be subject to the inspection of the board or any member thereof. The treasurer shall execute a bond to the city, with good and sufficient sureties, in such penal sum as the board shall direct, to be approved by the board, conditioned for the faithful performance of the duties of his office, and that he will safely keep and well and truly account for all moneys and property which may come to his hands as such treasurer, and that on the expiration of his term of office he will surrender and deliver over to his successor all unexpended moneys, and all securities and property which may have come to his hands as treasurer of such funds; and said bond shall be filed in the office where the records of the city are kept, and may be sued on in the name of said city, to the use of said board or any person or persons injured by a breach thereof.