Section 53. The county commissioners of the several counties shall (1) keep on file in their respective offices the duplicate roster of officers and employees of their county, furnished by the director under section fifty; (2) receive and forward to the board, with their report and recommendations thereon, appeals, as provided in section fifty-two; (3) receive and act upon recommendations for salary increases, as provided in section fifty-four, and (4) perform such other functions and duties as may be imposed upon them by said sections forty-eight to fifty-six, inclusive. They may also recommend to the board amendments to the classification and compensation plans and to the rules relating thereto. They shall be entitled to be heard in the determination of questions of classification and allocation on appeal to the board, or otherwise.