Section 3. (1) Kind of Membership. — (a) Membership in a system shall consist of two kinds as follows:—

(i) Member in Service.— Any member who is regularly employed in the performance of his duties, except a member retired for disability who upon partial recovery is restored to active service as provided for in paragraph (2) (a) of section eight. Any member in service shall continue as such during any period of authorized leave of absence with pay or during any period of authorized leave of absence without pay if such leave is due to his mental or physical incapacity for duty or if such authorized leave of absence without pay is for not more than one year or is to permit such member to perform his duties as a member of a retirement board. In any event the status of a member in service shall continue as such until his death or until his prior separation from the service becomes effective by reason of his retirement, resignation, failure of re-election or reappointment, removal or discharge from his office or position, or by reason of an authorized leave of absence without pay other than as provided for in this clause. Any member in service shall have full voting powers in the system as provided for in section twenty of this chapter and in section sixteen of chapter fifteen.

(ii) Member Inactive. — Any member in service who has been retired and who is receiving a retirement allowance, any member in service whose employment has been terminated and who may be entitled to any present or potential retirement allowance or to a return of his accumulated total deductions under the provisions of sections one to twenty-eight inclusive, or any member in service who is on an authorized leave of absence without pay other than as provided for in clause (i) of this paragraph. Any member in-active shall have full voting rights as provided for in section twenty of this chapter and in section sixteen of chapter fifteen.

(b) A beneficiary shall not be deemed to be a member of the system nor shall he have any voting rights therein.

(c) No description of a person having any rights or privileges under the provisions of sections one to twenty-eight inclusive, such as member in service, member inactive, beneficiary or otherwise, shall serve to deprive him of any such rights or privileges. A member shall retain his membership in the system so long as he is living and entitled to any present or potential benefit therein.

(2) Eligibility for Membership. — (a) Membership in a system as a member in service as defined in clause (i) of paragraph (1) (a) of this section shall comprise the following persons:—

(i) Any employee who is a present member in service, including any employee for whom regular deductions are being made whether or not he was classified as a member under provisions of earlier laws;

(ii) Any employee in active service who is not now a member but who, while under the maximum age for the group in which he would be classified, hereafter files with the board on a prescribed form a written application for membership, subject to the provisions of sections one to twenty-eight inclusive; provided, that during his present period of service he had previously been eligible for membership;

(iii) Any person who hereafter resigns, transfers or is promoted from a position in the service under which he had inchoate rights to a non-contributory pension under this chapter or under corresponding provisions of earlier laws or of any other general or special law, to accept a position subject to the provisions of sections one to twenty-eight inclusive, if at the time of such resignation, transfer or promotion he is under the maximum age for the group in which he would be classified;

(iv) Any person, except as specifically otherwise provided for in sections one to twenty-eight, inclusive, who enters or re-enters the service as an employee of the commonwealth, a teacher as defined in section one, or an employee of any political subdivision of the commonwealth for which a system established under the provisions of such sections, or under corresponding provisions of earlier laws, is in operation on the date when he becomes an employee; provided, that any such person who becomes regularly employed, as determined by the board as provided for in paragraph (d) of this subdivision, on a part-time, provisional, temporary, temporary provisional, seasonal or intermittent basis, shall become a member in service, if he is to be classified in Group 1, upon the completion of six calendar months of service, and any other such person shall become a member in service upon his entry into service; and provided, further, that a physician or dentist who is employed as an intern in a municipal hospital shall not become a member unless he files a written application for membership within ninety days of his appointment.

(v) Any state official as defined in section one hereafter appointed to office who files with the board on a prescribed form a written application for membership within ninety days after the date of assuming the duties of his position; provided, that a member becoming a state official shall retain his membership and a state official who is a member shall remain a member upon his reappointment or upon his appointment or election to any other position which would otherwise entitle him to membership;

(vi) Any person hereafter elected by popular vote to a state, county or municipal office or position who files with the board on a prescribed form a written application for membership within ninety days after the date of assuming office; provided, that a member becoming an elected official shall retain his membership and an elected official who is a member shall remain a member upon his re-election or upon his election or appointment to any other position which would otherwise entitle him to membership;

(vii) Any person who hereafter is reinstated to or who re-enters the active service of the governmental unit in which he was formerly employed as provided for in subdivision (6) of this section; provided, that any such person who fails to pay into the annuity savings fund of the system the amount of the accumulated regular deductions, if any, withdrawn by him together with buyback interest to the date of reemployment, or fails to make provision for payment thereof, under the terms set forth in such subdivision, shall be considered as a person first entering the employ of such governmental unit and shall become a member in service only under the conditions applicable to such person as set forth in this section;

(viii) Any employee who enters the active service of any governmental unit and who was a member of any system established under the provisions of sections one to twenty-eight inclusive, or under corresponding provisions of earlier laws or of any special law, and who hereafter transfers or re-establishes his membership as provided for in subdivision (8) of this section to or in the system which pertains to such governmental unit; provided, that any such employee who fails to transfer or re-establish his membership as so provided for shall be considered as a person first entering the employ of such governmental unit and shall become a member in service only under the conditions applicable to such person as set forth in this section; and

(ix) Any member retired for disability who upon recovery hereafter is restored to full active service as provided for in paragraph (2) (b) of section eight.

(x) Any employee as defined in section one.

(xi) Any employee, any part or all of whose salary, wages or other compensation is derived from federal grants made to the commonwealth or to any political subdivision thereof, which federal grants are used by the commonwealth or political subdivision for the payment of salaries, and who as a result thereof is eligible for membership in the United States civil service retirement system, or who otherwise is eligible for such membership, and who also is eligible for membership in any retirement system established under this act, may have such portion of his salary, wages or other compensation as is derived from federal grants included in his regular compensation as defined by section one, but as a condition precedent to membership, he shall file an affidavit with the retirement board certifying that he is not a member of the United States civil service retirement system, eligible to make contributions thereto based upon his current salary. If the employee certifies that he is a member of the United States civil service retirement system, eligible to make contributions thereto based upon his current salary, he thereby waives all rights to membership in any retirement system established under this chapter, and no deductions shall be made from his compensation for any retirement system established under this chapter. If, when becoming a member of a retirement system established under this chapter, he is not a member of the United States civil service retirement system, eligible to make contributions thereto based upon his current salary, but later at any time before retirement becomes a member of the United States civil service retirement system, except after resignation or discharge from the service which makes him eligible to membership in a retirement system established under this chapter, he shall cease to be a member of any retirement system established under this chapter, and his accumulated deductions shall be returned to him. When he or any beneficiary of his becomes eligible to receive any benefit under this chapter, he or his beneficiary, as a condition precedent to the receipt of such benefit, shall file an affidavit stating that the member is not or was not at his death a member of or eligible to receive any benefits under the United States civil service retirement system. Eligibility for membership in a retirement system established under this chapter and the right to receive a retirement allowance or benefit thereunder shall not be affected by the receipt of a federal pension or retirement allowance by a ''veteran'' for federal service, as defined in section one, or by any potential right thereto. Any employee who on January first, nineteen hundred and fifty-two was a member of the United States civil service retirement system and also a member of a retirement system established under this chapter, and any employee who was a member of the United States civil service retirement system and thereafter ceased to be a federal employee and became eligible for membership in a retirement system established under this chapter, and any employee who was a member under this chapter and thereafter resigned or was discharged and became a federal employee, may continue his membership in both systems on the condition that he shall at his retirement, or his beneficiary shall at his death, present to the retirement board established under this chapter proof of the amount of the retirement or survivorship allowance to be received from the United States civil service retirement system, and the retirement or survivorship allowance from the system established under this chapter shall be fixed at an amount which shall not exceed the difference between the annual federal retirement or survivorship allowance and the largest annual salary received by the employee during a calendar year of the employment which made him eligible for membership in the retirement system established under this chapter.

[There are no clauses (xii) and (xiii).]

(xiv) Any person who is appointed as a member of the judiciary on or after January second, nineteen hundred and seventy-five, shall become a member subject to the provisions of section sixty-five D.

(b) Any person who is an employee of any governmental unit on the date when a system established under the provisions of sections one to twenty-eight, inclusive, or under corresponding provisions of earlier laws, hereafter becomes operative therein, shall become a member in service as of such date unless within ninety days thereafter he shall file with the board on a prescribed form a notice of his election not to become a member and a duly executed waiver of all present and prospective benefits which might otherwise accrue to him if he became a member. No other pension or retirement law of the commonwealth whether general or special shall be applicable to any such member on or after the date such system becomes operative in such governmental unit, except as otherwise provided for in subdivision (7) of this section or in section twenty-five. In so far as practicable and not later than sixty days after the date such a system becomes operative in such governmental unit, the board shall notify each such employee in writing, or through meetings duly announced or by other means, of his rights and duties if he becomes a member and shall furnish him with a prescribed form to be filed with the board upon which he may give notice of his election to become a member in service or not to become a member, as he may elect.

(c) Any employee otherwise eligible for membership, who has elected not to become a member in service, may thereafter apply for and be admitted to membership upon the terms and conditions set forth in subdivision (3) or (8) of this section if on the date of application he is under the maximum age for his group.

(d) In all cases involving part-time, provisional, temporary, temporary provisional, seasonal or intermittent employment or service of any employee in any governmental unit, including such employment or service of any state official, the board shall have and exercise full jurisdiction to determine such employee's eligibility for membership; provided, that any person holding a position for which the annual compensation is fixed in an amount of two hundred dollars or less shall not be eligible for membership except by vote of the board; and provided further, that any teacher employed in the school department of the city of Boston on a provisional, temporary, temporary provisional or similar basis shall, upon the completion of a school year of service in the public schools of said city, become a member in service of the Boston retirement system. For the purposes of this paragraph, a school year of service shall be deemed to have been completed upon the termination of a school year in which the teacher, while holding a certificate granted by the board of education under section thirty-eight G of chapter seventy-one or while exempt from the provisions of said section because of employment as a teacher in the service of said city prior to the effective date of said section thirty-eight G, has actually performed teaching duties on more than one hundred and twenty school days, whether or not consecutive, in such school year.

[There is no paragraph (e).]

(f) Any employee who was not eligible for membership because of originally entering the service of any governmental unit after attaining age 60 but before attaining age 65, may apply for and be admitted upon the terms and conditions set forth in subdivisions (3) and (3A).

(g) Department heads shall furnish to the board within thirty days after employing any new personnel or after the receipt of a written request therefor, a statement giving the name, address, title, rate of regular compensation, duties, date of birth and length and class of service of each employee in his department, and shall notify the board within thirty days of any change in the title, address, rate of compensation, duties or service of any employee in his department. Thereupon the board shall classify each member in one of the following groups; provided that a member entering service prior to April 2, 2012 must be actively employed in a Group 2 or Group 4 position by a governmental unit which is subject to a retirement system under chapter 32, and must be actively performing the duties of said position for which the member seeks classification for not less than 12 consecutive months immediately preceding termination or retirement in order to qualify for the retirement allowance calculation of said group contained in subdivision (2) of section 5:

Group 1. — Officials and general employees including clerical, administrative and technical workers, laborers, mechanics and all others not otherwise classified.

Group 2. — Public works building police; permanent watershed guards and permanent park police; University of Massachusetts police; employees of the Massachusetts Port Authority, comprising guards, guard sergeants, head guard and chief of waterfront police; officials and employees of the office of public safety and inspections of the division of professional licensure and the division of inspection of the department of fire services having police powers; employees of a municipal department who are employed as fire or police signal operators or signal maintenance repairmen; ambulance attendants of a municipal department who are required to respond to fires and perform duties assigned to them; employees of a city or town who are employed as licensed electricians and elevator maintenance men employed by a county; employees of the South Essex sewerage district who are employed as licensed electricians; employees of Cushing hospital; employees of the trial court of the commonwealth who hold the position of chief probation officer, assistant chief probation officer, probation officer in charge or probation officer, chief court officer, assistant chief court officer or court officer; officers and employees of the general court having police powers; employees of the commonwealth or of any county, regardless of any official classification, except the sheriff, superintendent, deputy superintendent, assistant deputy superintendent and correction officers of county correctional facilities, whose regular and major duties require them to have the care, custody, instruction or other supervision of prisoners; employees of the department of children and families holding the title of social worker A/B, C or D or successive titles who have been employed in such titles for 10 years or more; and employees of the commonwealth or of any county whose regular and major duties require them to have the care, custody, instruction or other supervision of parolees or persons who are mentally ill or mentally defective or defective delinquents or wayward children and employees of Cushing hospital.

Group 3. — Officers and inspectors of the department of state police referred to in section twenty-six, who shall be retired and receive retirement allowances as provided for in said section and in sections six and seven, anything in sections one to twenty-eight, inclusive, to the contrary notwithstanding.

Group 4. — Division of law enforcement of the department of fisheries, wildlife and recreational vehicles; conservation officer of the city of Haverhill having duties similar to a law enforcement officer of the department of fisheries, wildlife and recreational vehicles; employees of the Massachusetts Port Authority at the General Edward Lawrence Logan International Airport, comprising permanent crash crewmen, fire control men, assistant fire control men; members of police and fire departments not classified in Group 1; any police officer of the Massachusetts Bay Transportation Authority; employees whose regular compensation is paid by the United States from funds allocated to the Massachusetts National Guard and who are regularly and permanently employed under the control of the military department of the commonwealth and whose duties in such employment require substantially all normal working hours and whose continued employment is based upon federal recognition in the Massachusetts National Guard; members of the Massachusetts military reservation fire department; members of the 104th fighter wing fire department; members of the Devens fire department established pursuant to chapter 498 of the acts of 1993; employees of a municipal gas or electric generating or distribution plant who are employed as linemen, electric switchboard operators, electric maintenance men, steam engineers, boiler operators, firemen, oilers, mechanical maintenance men, and supervisors of said employees who shall include managers and assistant managers; employees of the Massachusetts Port Authority who are employed as licensed electricians, utility technicians, steam engineers, watch engineers, boiler operators, or steam firemen, and supervisors of said employees, at an electrical generating or distribution plant; employees of the department of correction who are employed at any correctional institution or prison camp under the control of said department and who hold the position of correction officer, female correction officer, industrial instructor, recreation officer, assistant industrial shop manager, industrial shop manager, assistant to the supervisor of industries, supervisor of industries, senior correction officer, senior female correction officer, supervising correction officer, supervising female correction officer, prison camp officer, senior prison camp officer, supervising prison camp officer, assistant deputy superintendent; employees of the parole board who hold the position of parole officer or parole supervisor; chief of security for the University of Massachusetts medical school or supervising identification agent; employees who hold the position of state hospital steward in the department of correction; the sheriff, superintendent, assistant superintendent, assistant deputy superintendent and correction officers of county correctional facilities; district attorneys, assistant district attorneys who have been employed in such capacity for ten years or more; the chief fire warden and the district fire wardens in the executive office of environmental affairs and the fire marshal of the department of fire services in the executive office of public safety; but the fire marshal shall have been a member of group 4 for ten years or have had ten years or more employment at the department of fire services or its predecessor agencies, the division of fire prevention and the Massachusetts firefighting academy, before being eligible for benefits under this section.

A municipality may elect to place in Group 4 uniformed employees of a municipal or public emergency medical service who are certified at any level by the department of public health as an emergency medical technician. This section shall take effect in a municipality upon its acceptance in the following manner: in a city having a Plan D or Plan E charter, by majority vote of its city council and approved by the manager; in any other city by majority vote of the city council and approved by the mayor; in a town, by vote of the board of selectmen.

(h) Nothing contained in this section shall be construed to impair the rights of any member whose office or position is subject to chapter thirty-one or to the rules and regulations made under authority thereof.

(3) Late Entry into Membership. — Notwithstanding his filing of notice and waiver under paragraph (b) of subdivision (2) of this section, any employee who, having or having had the right to become a member, failed to become or elected not to become a member, may apply for and be admitted to membership if under the maximum age for his group on the date of his application; provided, that during his present period of service he had previously been eligible for membership; and any employee who, having had the right to become a member of any retirement system established under the provisions of this chapter, or under corresponding provisions of earlier laws or any special law, failed to become or elected not to become a member, may apply for and be admitted to membership if under the maximum age for his group on the date of his application. No employee shall otherwise be admitted to membership except by vote of the retirement board of the system for which application is made, and then only if that board finds that his failure to become or his election not to become a member was caused by circumstances other than those generally applicable to employees. No such member shall be entitled to full credit for service rendered prior to the date of his becoming a member, unless before the date any retirement allowance becomes effective for him he shall have paid into the annuity savings fund of the system in one sum, or in instalments, upon such terms and conditions as the board may prescribe, make-up payments of an amount equal to that which would have been withheld as regular deductions from his regular compensation had he joined the system at his earliest opportunity, together with buyback interest. Upon the completion of such make-up payments such member shall be entitled to all creditable service to which he would have been entitled had he joined the system when first eligible to become a member. In the event any retirement allowance becomes effective for him before the completion of such make-up payments, such member shall, in addition to credit for his actual membership service, be entitled to credit for that proportion of his service rendered prior to the date of his becoming a member which the total amount of his make-up payments actually made, together with buyback interest thereon to the date his retirement allowance becomes effective, bears to the total amount of what his make-up payments, together with buyback interest thereon to such latter date, would have been had he made payment thereof in one sum on such latter date.

(3A) Equal Privileges For Certain Members. — An employee who is a member of a retirement system or who is entitled to become a member and who fulfills all the conditions required for a member during the period commencing July first, nineteen hundred and thirty-seven, and ending January first, nineteen hundred and forty-six, may pay into the annuity saving fund of the system in one sum, or in instalments, upon such terms and conditions as the board may prescribe, make-up payments of an amount not to exceed that which would have been withheld as regular deductions from his regular compensation had the deductions been based on his total earnings rather than the prescribed limit or limits in force during this period, together with interest on such make-up payments. Upon the completion of payment of such make-up payments, together with interest thereon, such member shall be entitled to such additional retirement allowance as said additional contributions would entitle him. In the event such member retires before the completion of payment of such make-up payments and interest thereon, such member shall, in addition to the retirement allowance provided by his regular contribution, be entitled to credit for that proportion of his additional contribution made prior to the time of his retirement.

(4) Credit for Teachers for Out-of-State Service. — Any member in service, or any member inactive on authorized leave of absence of the teachers' retirement system, or any member in service, or any member inactive on authorized leave of absence of any other contributory retirement system who is employed in a teaching position or as a principal, supervisor or president in a school or college, or employed in the department of education as supervisor of teachers or of educational methods, who had rendered service in any other state for any previous period as a teacher, principal, supervisor or superintendent in the public day schools or other day school under exclusive public control and supervision, or in a public academy, or as a teacher, principal, supervisor or president in a state normal school, state teachers college or like institution, or other college under exclusive public control and supervision, or in a public academy, or who was employed in a state department of education as supervisor of teachers or of educational methods, may, before the date any retirement allowance becomes effective for him, pay into the annuity savings fund of the system in one sum, or in instalments, upon such terms and conditions as the board may prescribe, an amount equal to that which would have been withheld as regular deductions from his regular compensation for such previous period, or most recent portion thereof, as he may elect, had such service been rendered in a public school of the commonwealth and had he been a member of the teachers' retirement system during the period the service was rendered; provided, that for such service which was rendered prior to July first, nineteen hundred and fourteen, payment shall be made equal to the regular deductions which would have been withheld from his regular compensation if the teachers' retirement system, as established by chapter eight hundred and thirty-two of the acts of nineteen hundred and thirteen, had been in effect during the period the service was rendered, and the interest to July first, nineteen hundred and fourteen, shall be computed at the rate of three per cent. Payment shall not be made and no credit shall be allowed for service in other states in excess of the total Massachusetts service to which the member would be entitled to receive credit if he remained in service to age sixty-five, with a maximum credit for service in other states not to exceed ten years; provided, that no credit shall be allowed and no payment shall be accepted for any service for which the member shall be entitled to receive a retirement allowance from any other state. In addition to the payment of such sum or instalments thereof, such member shall also pay into the annuity savings fund an amount of interest such that at the completion of such payments the value of his accumulated payments, together with buyback interest thereon, actually made on account of such previous out-of-state service, shall equal the value of his accumulated buyback deductions which would have resulted if regular deductions had been made when regular compensation for such service was actually received. Upon the completion of such payments, such member shall receive the same credit for such period of his previous out-of-state service, or portion thereof elected, as would have been allowed if such service had been rendered by him in a public school of the commonwealth. Such member shall furnish the board with such information as it shall require to determine the amount to be paid and the credit to be allowed under this subdivision. At the time a retirement allowance becomes due to a member or to a beneficiary under option (d) of subdivision (2) of section twelve, if the Massachusetts service on the date either retirement allowance becomes effective, or on the date the member attained age sixty-five, whichever first occurs, is less than the service in other states for which the member has paid, credit shall be allowed only for the most recent service rendered in other states equal to such Massachusetts service, and the amount paid for additional service shall be refunded with accumulated interest, refund to be made only when the retirement allowance becomes due to the member or to the beneficiary under option (d) of subdivision (2) of section twelve, and if it is found that payment has been accepted for any service for which the member is entitled to a retirement allowance from any other state, the amount paid for such service with accumulated interest shall also be refunded with no retirement credit allowed.

For the purposes of this subdivision the words ''service in any other state for any previous period as a teacher, principal, supervisor or superintendent in the public day schools or other day school under exclusive public control and supervision'' shall be deemed to include service rendered in an overseas dependent school conducted under the supervision of the department of defense of the government of the United States, and service rendered in the public schools of the Commonwealth of Puerto Rico; provided, that any credit to be allowed shall not exceed five years of the maximum credit of ten years allowable for service in other states as provided in this section.

(4A) Credit for Teachers for Nonpublic School Service. — Any member in service, or any member inactive on authorized leave of absence of the teachers' retirement system or the state retirement system or the Boston retirement system, who holds a certificate issued by the department of education or is exempted from the requirement of certification or any member who is employed in a public institution of higher education as a faculty member or professional employee not under the jurisdiction of the human resources division within the executive office for administration and finance classification system and who was previously engaged in teaching pupils or as an administrator in a nonpublic school prior to January first, nineteen hundred and seventy-three may, before the date any retirement allowance becomes effective for him, pay into the annuity savings fund of the appropriate system in one sum, or in installments, upon such terms and conditions as the board may prescribe, an amount equal to that which would have been withheld as regular deductions from his regular compensation for such previous period, or most recent portion thereof, as he may elect, had such service been rendered in a public school of the commonwealth or public institution of higher education and had he been a member of the teachers' retirement system or the state retirement system during the period such service was rendered. Payment shall not be made and no credit shall be allowed for service in nonpublic schools in excess of the total Massachusetts service to which the member would be entitled to receive credit if he remained in service to age sixty-five, with a maximum credit for service in nonpublic schools not to exceed ten years; provided that no credit shall be allowed and no payment shall be accepted for any service on account of which the member shall be entitled to receive a retirement allowance or other similar payment from the nonpublic school system, the federal government or any other source. In addition to the payment of such sum, or installments thereof, such member shall also pay into the appropriate annuity savings fund an amount of interest such that at the completion of such payments the value of his accumulated payments, together with buyback interest thereon, actually made on account of such previous nonpublic school service, shall equal the value of his accumulated buyback deductions which would have resulted if regular deductions had been made when regular compensation for such service was actually received. Upon the completion of such payments, such member shall receive the same credit for such period of his previous nonpublic school service, or portion thereof elected, as would have been allowed if such service had been rendered by him in a public school of the commonwealth or public institution of higher education. Such member shall furnish the appropriate board with such information as it shall require to determine the amount, to be paid and the credit to be allowed under this subdivision. At the time a retirement allowance becomes due to a member or to a beneficiary under option (d) of subdivision (2) of section twelve, if the Massachusetts service on the date either retirement allowance becomes effective, or on the date the member attained the age of sixty-five, whichever first occurs, is less than the service in nonpublic schools for which the member has paid, credit shall be allowed only for the most recent service rendered in nonpublic schools equal to such Massachusetts service, and the amount paid for additional service shall be refunded with accumulated interest, refund only to be made when the retirement allowance becomes due to the member or to the beneficiary under option (d) of subdivision (2) of section twelve, and if it is found that payment has been accepted for any service for which the member is entitled to a retirement allowance from any nonpublic school system, the amount paid for such service with accumulated interest shall also be refunded with no retirement credit allowed.

(5) Credit for Members for Intra–State Service in Governmental Units Where No System Existed. — Any member of any system who had rendered service as an employee of any governmental unit other than that by which he is presently employed, for any previous period during which the first governmental unit had no contributory retirement system or during which he had inchoate rights to a non-contributory pension or in a position which was not subject to an existing retirement system, or which was specifically excluded therefrom but which would be covered under the law now in effect, or any member who during any period of service for the governmental unit by which he is presently employed had such inchoate rights or was so excluded from membership, or any member of any retirement system who had rendered service as an employee in the governmental unit by which he is presently employed and who separated from such service and who had a right to become a member of the existing retirement system pertaining thereto, but who did not exercise such right before separation from such service, or any member who had a right to become a member of an existing system in any other governmental unit and who did not exercise such right, and who, when he left the service of such other governmental unit, had such right, or any member of any system who rendered service in any governmental unit other than that by which he is presently employed, in a temporary, provisional, or substitute position and who was excluded from membership by the rules of any board, may, before the date any retirement allowance becomes effective for him, pay into the annuity savings fund of the system in one sum, or in instalments, upon such terms as the board may prescribe, an amount equal to that which would have been withheld as regular deductions from his regular compensation for such previous period, or most recent portion thereof, as he may elect, in no event aggregating more than twenty years, had such service been rendered in the governmental unit by which he is presently employed and in a position subject to the provisions of this chapter, or to corresponding provisions of earlier laws. In addition to the payment of such sum or instalments thereof, such member shall also pay into the annuity savings fund an amount of interest such that at the completion of such payments the value of his accumulated payments, together with buyback interest thereon, actually made on account of such previous intrastate service shall equal the value of his accumulated buyback deductions which would have resulted if regular deductions had been made when regular compensation for such service was actually received. Upon the completion of such payments such member shall receive the same credit for such period of his previous intrastate service or portion thereof elected as would have been allowed if such service had been rendered by him in the governmental unit by which he is presently employed. Such member shall furnish the board with such information as it shall require to determine the amount to be paid and the credit to be allowed under this subdivision.

(a) Any person who is now a member or who becomes a member of a system applicable to any governmental unit shall be given credit in such system for any service rendered as a constitutional officer or as a member of the general court by depositing in the annuity savings fund of such system such sums and under such conditions as are set forth under said sections.

[There is no paragraph (b).]

(6) Leave of Absence and Reinstatement to or Re-entry into Active Service. — (a) Leaves and periods of absence of any member duly authorized with full regular compensation shall not be deemed an interruption of membership or service and shall be counted as full creditable service. Leaves and periods of absence of any member duly authorized without regular compensation or with partial regular compensation, while not to be deemed a termination of membership or service, shall not be counted as creditable service except as specifically otherwise provided for in section four. The board shall have full power to make such rules, regulations and findings as it may deem necessary, consistent with the provisions of sections one to twenty-eight inclusive, relating to leaves and periods of absence and the rights and duties of any member during the same as will effectuate the purposes of such sections.

(b) Any member inactive whose service has been terminated otherwise than by retirement but whose membership has been retained by failure to withdraw his accumulated total deductions, shall become a member in service upon his reinstatement to or re-entry into the active service of his former employer in a position which is subject to the provisions of sections one to twenty-eight inclusive.

(c) Any former member who is reinstated to or who re-enters the active service of the governmental unit in which he was formerly employed to serve in a position which is subject to the provisions of this chapter, within two years from the date of his separation therefrom, may again become a member in service and may pay into the annuity savings fund of the system in one make-up sum, or in installments upon such terms and conditions as the board may prescribe, an amount equal to the accumulated regular deduction withdrawn by him, together with the buyback interest to the date of reemployment. No such member shall be eligible for any disability benefit under the provisions of this chapter, until such member makes a repayment of accumulated regular deductions and buyback interest, to said respective retirement system. Upon making such make-up payment such member shall be entitled to all creditable service resulting from such previous employment.

(d) Any former member who is reinstated to or who re-enters the active service of the governmental unit in which he was formerly employed to serve in a position which is subject to the provision of this chapter, more than two years after the date of his last separation therefrom may, before the date any retirement allowance becomes effective for him, pay into the annuity savings fund of the system in one sum, or in instalments, upon such terms and conditions as the board may prescribe, make-up payments of an amount equal to the accumulated regular deductions withdrawn by him, together with buyback interest. Upon such re-employment and upon making such payment in one sum or upon making provision for payment thereof in instalments, as the case may be, such former member shall again become a member. A member who did not, at the earliest opportunity, either return in one sum the permitted make-up payment, or provide for such repayment in instalments, and whose membership was contingent on such payment either in one sum or his making provision for the payment thereof in instalments, may, during the period permitted for such payment, also pay as an additional make-up payment the deductions omitted from the date when the make-up payment for previous membership could first have been paid, with buyback interest. Upon the completion of such make-up payments such member shall be entitled to all creditable service resulting from his previous employment. In the event any retirement allowance becomes effective for him before the completion of such make-up payments, such member shall, in addition to credit for his actual membership service rendered since the date of his last becoming a member, be entitled to credit for that proportion of his previous creditable service rendered prior to such date which the total amount of his make-up payments actually made, together with buyback interest thereon to the date his retirement allowance becomes effective, bears to the total amount of what his make-up payments, together with buyback interest thereon to such latter date, would have been had he made payment thereof in one sum on such latter date.

(e) Anything in sections one to twenty-eight inclusive to the contrary notwithstanding, no person who becomes a member under subdivision (3) of this section, and no member who is reinstated to or who re-enters active service as provided for in paragraph (b), (c) or (d) of this subdivision, or who transfers or re-establishes his membership as provided for in subdivision (8) of this section, shall be eligible to receive a superannuation retirement allowance, an ordinary disability retirement allowance or a termination retirement allowance unless and until he shall have been in active service for at least two consecutive years, including any period or periods of leave of absence credited as membership service, subsequent to the date of commencement of his new employment, or unless, in the case of any member who is reinstated to or who re-enters active service as provided for in paragraph (b) of this subdivision or who transfers his membership as provided for in paragraph (8) (a) of this section, he was eligible to receive a retirement allowance under the provisions of section ten at the time of his last separation from service; provided that, in the case of a member whose account is transferred under said paragraph (8) (a), this paragraph shall not apply after the member has rendered service or attained an age so that he would have been eligible to retire if he had continued to be a member of the retirement system from which his account was transferred.

(f) Any employee who last terminated his service in any political subdivision of the commonwealth before a contributory retirement system established under the provisions of this chapter, or under corresponding provisions of earlier laws or under any special law, became operative in such political subdivision and who is reinstated to or who re-enters the active service of such political subdivision after such a system becomes operative therein shall become a member upon his re-employment in a position which is subject to the provisions of such retirement system. Upon becoming a member he shall be entitled to all creditable service resulting from his previous employment in such political subdivision. In no event shall any such member be eligible to receive a superannuation retirement allowance or a termination retirement allowance unless and until he shall have been in active service for at least five years, including any period or periods of leave of absence credited as membership service, subsequent to the date of commencement of his new employment.

(7) Dual Membership. — (a) Any person employed by two or more governmental units which have established contributory retirement systems under the provisions of sections one to twenty-eight inclusive, or under corresponding provisions of earlier laws, shall, subject to the provisions of such sections, become a member in service of each such system to which he is eligible by reason of his employment in such governmental units and shall receive pensions, retirement allowances or other benefits from each such system according to the applicable provisions of such sections. If any such person is or becomes a member of two or more such systems on or after January first, nineteen hundred and forty-six, the treasurer of each such governmental unit shall withhold five per cent of the regular compensation due such member on each pay day from such governmental unit for deposit to the credit of such member in the annuity savings fund of the appropriate system.

(b) In no event shall the total benefits received by such member from all such systems be greater than he would have received had his total regular compensation been received from a single governmental unit. The amount of any pension, retirement allowance or other benefit to be paid on account of any person who is a member of two or more such systems shall be computed and paid in such proportions as may be ordered by the actuary. No pension or retirement allowance shall become effective on account of any such person's membership in one system until the date the member terminates his service in any other governmental unit. Any board may conduct separate medical examinations for any member who is a member of two or more systems; provided, however, that the commission may suspend or otherwise limit such examination upon recommendation of the regional medical panel if it determines such second examination would be unnecessary based on the evidence of the first examination. Any such person so jointly employed shall have all the rights and be subject to the liabilities under the provisions of sections one to twenty-eight, inclusive, as a member of each such system, and his liability for regular deductions and his right to benefits from each system shall be based upon his regular compensation received from the governmental unit to which such system pertains.

(c) Any person who is a member of two or more systems and who on or after January first, nineteen hundred and forty-six, receives regular compensation paid jointly by two or more governmental units, shall, subject to the provisions of sections one to twenty-eight inclusive, while continuing in such joint employment, be allowed creditable service in each system for all such employment in the governmental unit to which each system pertains. In no event shall any such person during such joint employment be allowed creditable service in any one system for a total period of service longer than he would have been credited with had he been a full-time employee of the governmental unit to which such system pertains. In all cases of joint employment involving membership in two or more such systems, the amount of creditable service allowed to any such person shall be subject to the approval of the actuary.

(d) If any person who is a member of two or more systems terminates his service in one governmental unit other than by retirement but continues in service in one or more other governmental units, his membership in the system pertaining to the former governmental unit shall thereupon be transferred to the system of the governmental unit to which he is devoting the major portion of his employment and the provisions of subdivision (8) of this section shall be applicable; provided, however, that an individual awarded a disability pension from the system pertaining to the former governmental unit who continues his service in one or more other governmental units shall waive receipt of the disability retirement allowance during the period of such continued service, and provided further, that the membership of such individual awarded a disability pension shall not thereupon be transferred to the system of the governmental unit to which he is donating the major portion of his employment. In no event shall any member be eligible to receive a retirement allowance from one system while continuing in service in any governmental unit, except as provided for in section ninety-one, or in section twenty-six of chapter six hundred and seventy of the acts of nineteen hundred and forty-one, or in chapter sixteen of the acts of nineteen hundred and forty-two as amended. In no event shall any member who terminates his service in one governmental unit be entitled to withdraw his accumulated total deductions from the system pertaining to such governmental unit while still retaining his membership in any other system, except for the purpose of transfer thereof to such other system.

(e) Any person who is a member of one or more contributory retirement systems established under the provisions of sections one to twenty-eight inclusive, or under corresponding provisions of earlier laws, and who is also a member of a contributory retirement system established and operative under any special law, shall be subject to the provisions of this subdivision to the extent such provisions are not inconsistent with those of the special law. In all such cases the amount of creditable service allowed to any such person and the amount of any pension, retirement allowance or other benefit to be paid on his account shall be computed by the actuary.

(f) The provisions of paragraphs (a) to (e) inclusive of this subdivision shall not apply to any person employed by Suffolk County whose regular compensation received from the county at the time of his employment was more than one half of his combined regular compensation from all governmental units.

(g) Any person retired under the provisions of this chapter, or under corresponding provisions of earlier laws or of any other general or special law, shall receive only such benefits as are allowed or granted by the particular provisions of the law under which he is retired.

(8) Transfer or Re-establishment of Membership. — (a) Any member of any contributory retirement system established under the provisions of sections one to twenty-eight inclusive, or under corresponding provisions of earlier laws or of any special law, who, while still a member and before the date any retirement allowance becomes effective for him, becomes employed in a position in any other governmental unit in which such a system is operative, shall thereupon have his membership transferred to the second system, or if a teacher as defined in section one shall retain his membership in the teachers' retirement system, and shall be entitled to all creditable service resulting from his previous employment; provided, that such position is subject to the provisions of the law pertaining to the second system or to the teachers' retirement system, as the case may be. Such transfer of membership, if required, shall be effectuated by transferring within ninety days after the date of commencement of his new employment the amount of the accumulated total deductions credited to his account in the annuity savings fund of the system from which he is being separated to the annuity savings fund of the second system.

(b) Any former member of any contributory retirement system established under the provisions of this chapter, or under corresponding provisions of earlier laws or of any special law, who subsequently becomes employed in a position in any other governmental unit in which such a system is operative, may, before the date any retirement allowance becomes effective for him, pay into the annuity savings fund of the system pertaining to his new employment in one sum, or in instalments, upon such terms and conditions as the board may prescribe, make-up payments of an amount equal to the accumulated regular deductions withdrawn by him from the system from which he last became separated, together with buyback interest; provided, that such position is subject to the provisions of the law relating to the system pertaining to his new employment. Upon commencing such employment and upon making such payment in one sum, or upon making provision for payment thereof in instalments, as the case may be, such former member shall become a member of the system pertaining to his new employment. A member who did not, at the earliest opportunity, either return in one sum the permitted make-up payment, or provide for such repayment in instalments, and whose membership was contingent on such payment either in one sum or his making provision for the payment thereof in instalments, may, during the period permitted for such payment, also pay as an additional make-up payment the deductions omitted from the date when the make-up payment for previous membership could first have been paid, with buyback interest. Notwithstanding any provision of this chapter to the contrary, a member who is reinstated to, or re-enters the active service of, a governmental unit, or who is eligible to receive credit for other service under this section, and who does not, (i) pay into the annuity savings fund of the system make-up payments of an amount equal to the accumulated regular deductions withdrawn by the member, together with buyback interest; or (ii) make provision for the repayment in installments, upon such terms and conditions as the board may prescribe, to pay into the annuity savings fund of the system make-up payments of an amount equal to the accumulated regular deductions withdrawn by the member, together with buyback interest, within 1 year from the date of reinstatement or re-entry or within 1 year after April 2, 2012, whichever is later, shall pay actuarial assumed interest instead of buyback interest on all make-up payments to be entitled to creditable service resulting from the previous employment. Upon the completion of such make-up payments such member shall be entitled to all creditable service resulting from his previous employment. In the event any retirement allowance becomes effective for him before the completion of such make-up payments, such member shall, in addition to credit for his actual membership service rendered since the date of his becoming a member of the system pertaining to his new employment, be entitled to credit for that proportion of his previous creditable service attributable to his former membership in the system from which he last became separated which the total amount of his make-up payments actually made, together with buyback interest thereon to the date his retirement allowance becomes effective, bears to the total amount of what his make-up payments, together with buyback interest thereon to such latter date, would have been had he made payment thereof in one sum on such latter date.

(c) Whenever any retired member or beneficiary receives a pension or survivor's allowance from a system pertaining to one governmental unit in a case where a portion of such pension or survivor's allowance is attributable to service in a second governmental unit to which another system pertains, the first governmental unit shall be reimbursed in full, in accordance with the provisions of this paragraph, by the second governmental unit for such portion of the pension as shall be computed by the actuary. The actuary shall consider length of service and whether the respective systems have elected to accept the provisions of paragraph (b1/2) of subdivision (1) of section twenty-two when computing such portions. No system which has not accepted the provisions of said paragraph shall be assessed any costs for service in any other system which has accepted the provisions of said paragraph. In any case where creditable service is allowed for any period served in the armed forces, where a member became employed in a position in a governmental unit other than the governmental unit wherein he was employed prior to entering such military service, the cost of any pension attributable to such creditable service shall be divided equally between the two retirement systems involved, and the actuary shall, on the same basis, determine the amount to be transferred from the special fund for military service credit, established under the provisions of subdivision (4) of section twenty-two, of the system of the governmental unit by which the member was employed prior to entering such military service to the special fund for military service credit in the second retirement system. The treasurer of the first governmental unit shall annually, on or before January fifteenth, upon the certification of the board of the system from which such disbursements have been made, notify the treasurer of the second governmental unit of the amount of reimbursement due therefrom for the previous fiscal year and such latter treasurer shall forthwith take such steps as may be necessary to insure prompt payment of such amount. All such payments due under the provisions of this paragraph from the second governmental unit shall be charged to the pension fund of the system pertaining thereto and as received they shall be credited to or appropriated for the pension fund of the system pertaining to the first governmental unit; provided, however, that if the commonwealth is the first governmental unit, any payments received shall be credited to the General Fund. In default of any such payment, the first governmental unit may maintain an action of contract to recover the same; provided, that there shall be no such reimbursement if the two systems involved are the state employees' retirement system and the teachers' retirement system.

(d) The pertinent provisions of this subdivision shall apply to the extent not inconsistent therewith to any person otherwise subject thereto who has transferred his employment from one governmental unit to another prior to January first, nineteen hundred and forty-six, as well as to any such person who so transfers his employment on or after such date. The provisions of paragraph (6) (e) of this section shall be applicable to any member whose membership is transferred or re-established as provided for in this subdivision.