The regional planning commission shall consist of nine persons. Members shall be appointed for six years; except, that the respective terms of seven of the members first appointed shall be one year, two years, two years, three years, four years, four years and five years; provided, that, if at the time of his appointment the appointee is a public officer or in the public service of the state or any of its political subdivisions and his incumbency as such public officer or servant expires previous to the term for which he is appointed on the regional planning commission, then his term on the commission shall terminate with the expiration of his incumbency as such public officer or servant, unless it is extended by the Governor, in which case such extension shall be for the remainder of the term for which he was originally appointed. The members shall serve without compensation but shall be paid their necessary expenses incurred in the performance of their duties. They may, after a public hearing, be removed by the Governor for inefficiency, neglect of duty, or malfeasance in office, and he shall file a written statement of his reasons therefor. Vacancies shall be filled by the Governor for the unexpired term.