Before the first meeting of each Congress the Clerk of the next preceding House of Representatives shall make a roll of the Representatives-elect, and place thereon the names of those persons, and of such persons only, whose credentials show that they were regularly elected in accordance with the laws of their States respectively, or the laws of the United States. In case of a vacancy in the office of Clerk of the House of Representatives, or of the absence or inability of the Clerk to discharge the duties imposed on him by law or custom relative to the preparation of the roll of Representatives or the organization of the House, those duties shall devolve on the Sergeant at Arms of the next preceding House of Representatives.