(1) With the exception of those employees who are excluded from membership as herein provided, all employees shall become members of the retirement system as follows:

(a) Every employee in city service as defined in this chapter, on July 1, 1939, shall become a member of the retirement system on that date.

(b) Every employee who enters or reenters city service after July 1, 1939, shall become a member of the retirement system upon the completion of six months of continuous service.

(2) The following shall be specifically exempted from the provisions of this chapter:

(a) Members of the police departments who are entitled to the benefits of the police relief and pension fund as established by state law.

(b) Members of the fire departments who are entitled to the benefits of the firefighters' relief and pension fund as established by state law.

(3) It shall be the duty of the head of each office or department to give immediate notice in writing to the board of administration of the change in status of any member of his or her office or department, resulting from transfer, promotion, leave of absence, resignation, reinstatement, dismissal or death. The head of each office or department shall furnish such other information concerning any member as the board may require.

(4) Each member shall be subject to all the provisions of this chapter and to all the rules and regulations adopted by the board of administration. Should the service of any member, in any period of ten consecutive years, amount to less than five years, or should he or she withdraw more than one quarter of his or her accumulated contributions, or should he or she die or be retired, he or she shall thereupon cease to be a member.