All persons who, at the time this Charter takes effect, are holding positions in the service of the City pursuant to appointment from eligible lists, or who have been continuously in the service of the City in the same position for the preceding five years, shall be deemed to hold such position as though appointed in accordance with the provisions of this Charter. Employees of any public utility acquired by the City, who are in the service of such utility at the time of its acquisition, shall be deemed to hold their positions as though appointed under the civil service provisions of this Charter; but vacancies thereafter occurring in such service shall be filled from eligible lists in the manner herein provided.