§ 51. County manager form. A county which shall adopt the county manager form of government shall have a county executive to be called "county manager." The board of supervisors shall appoint the county manager to serve during the pleasure of the board of supervisors. At the time of his appointment he need not be a resident of the county or the state, but during his term of office he shall reside within the county. No member of the board of supervisors shall, during the term for which he was elected, be eligible for appointment as county manager. Subject to any applicable provisions of the civil service law, the county manager shall appoint, supervise and at pleasure remove every other administrative officer and employee of the county except those elected by vote of the people and their subordinates, except that (1) the county manager may, when authorized by local law, serve without additional compensation as the head of one or more departments not administered by an elective official and (2) the county manager may delegate to any of his subordinates the power to appoint or remove persons working under the supervision of such subordinate. The foregoing provisions of this section, together with the other applicable provisions of this chapter, including those provisions which may be made applicable, shall constitute the structure of the county manager form of government authorized to be adopted by this chapter.