The treasurer shall be the custodian of said pension fund, subject to the control and direction of the board and shall keep a separate book and complete account concerning said fund, in such a manner as may be prescribed by the board, and the books and accounts shall always be subject to the inspection of the board or any member thereof, and said treasurer shall be personally liable, and also liable on his bond executed to the city for the purpose of becoming said officer of the city. On the expiration of his term of office, he will surrender and deliver over to his successor all unexpended moneys and all property and evidence of indebtedness, and all other papers and records which may have come to his possession as treasurer of such funds.