CUTTER, J.

The board seeks declaratory relief. The parties have agreed that the facts alleged in the bill are all the material facts and that inferences may be drawn as if the bill were a case stated. The case has been reported without decision. Mrs. McCormick became a thirty-hour-a-week floor-duty nurse in the Boston hospital department and a member of the Boston retirement system, effective June 2, 1954. See G.L.c. 32, §§ 1-28; St. 1947, c. 520. She received, through exposure to tuberculosis bacilli in the course of her employment during July and August, 1955, an injury compensable under the workmen's compensation provisions of G.L.c. 152, liability for which was redeemed by the city by a lump sum payment in March, 1960.

On October 5, 1955, Mrs. McCormick was granted a leave of absence for illness to March 5, 1956, which was successively extended to March 7, 1958. When she then neither returned to work nor requested a further leave, "she was automatically terminated as a . . . nurse."

On a prescribed form filed with the board about May 6, 1958, she "requested that she be paid the amount of her accumulated total [retirement] deductions." This payment was made about May 19, 1958.

At the time she filed this form with the board, "she had become totally and permanently incapacitated for further duty before attaining the maximum age for her group by reason of a personal injury sustained as a result of, and while in the performance of, her duties at a definite place and at a definite time after the date of her becoming a member, without serious and wilful misconduct on her part." About August 2, 1960, her counsel wrote to the board claiming for her accidental disability "retirement benefits for total and permanent incapacity . . . and requesting [an] official application form." The board received "a formal application for an accidental disability retirement, which . . . [Mrs. McCormick] withdrew on July 6, 1961, to eliminate questions as to the necessity of a tender of repayment of refunded accumulated total deductions as condition precedent to application." On that same day, she (without having become again employed by the city) "tendered to the . . . [board]: (1) the amount of her accumulated total deductions which had been paid to her . . . about May 19, 1958, together with . . . interest; and (2) an application for an accidental disability retirement allowance." The board has "refused to accept such tenders contending . . . that it is neither mandatory upon . . . [it], nor within . . . [its] power, to accept such tenders." The board further contends that Mrs. McCormick is barred from any retirement allowance by the instrument executed by her on May 6, 1958.

General Laws c. 32, § 7 (as amended through St. 1951, c. 545, § 1), provides for an accidental disability retirement allowance made up of two principal components. The first is a yearly pension "equal to two thirds of the average annual rate of . . . [the] regular compensation" for the twelve months period for which the member last received regular compensation prior to his or her retirement. See § 7 (2) (a) (ii). There is an additional pension where there are dependents of the member. See § 7 (2) (a) (iii). The other principal component is an annuity equal to the regular life annuity specified in § 12 (2), option (a), clause (i), the value of which "on the date such allowance becomes effective shall be the actuarial equivalent of . . . [the member's] accumulated regular deductions, if any, on such date." See § 7 (2) (a) (i). Pensions to members are paid from the pension fund of the system. See § 22 (3). The annuity is paid from the annuity reserve fund existing under § 22 (2), to which upon the retirement of a member, see § 22 (1), clause (1), his accumulated total deductions shall be transferred from his account in the system's annuity savings fund.

The present controversy appears to have arisen not only because of the great complexity of the relevant provisions of c. 32, but also because, when Mrs. McCormick requested the return of her accumulated total deductions, she had not claimed an accidental disability retirement allowance. The agreed facts indicate that she then could reasonably have claimed one. Whether either she or the board then knew of her potential claim does not appear. In view of the substantial pension to which she was entitled as part of this disability retirement allowance, we infer that, if she had then known of her claim and of her total disability, Mrs. McCormick would have sought the retirement allowance rather than the return of her accumulated deductions. We must determine whether under c. 32 the action which she then took now bars her (without consideration of possible relief for mutual mistake, see Reggio v. Warren, 207 Mass. 525, 533-538; see also Piea Realty Co. Inc. v. Papuzynski, 342 Mass. 240, 248) from obtaining at least the pension portion of her disability allowance.

Mrs. McCormick under § 3 (1) (a) (i) continued to be a "member in service" of the retirement system during her leaves of absence. See Gannon v. Contributory Retirement Appeal Bd. 338 Mass. 628, 631. See also § 14 (1) (a) and (c). Upon the automatic termination of her employment on March 7, 1958 (as a "member in service whose employment has been terminated . . . entitled to any . . . potential retirement allowance or to a return of . . . [her] accumulated total deductions" under §§ 1-28), she became a "member inactive." See c. 32, § 3 (1) (a) (ii). This description of her status in the system does not "serve to deprive . . . [her] of any . . . rights or privileges" under §§ 1-28. See § 3 (1) (c), which also provides that a "member shall retain . . . membership in the system so long as . . . living and entitled to any . . . potential benefit therein." Upon the agreed facts, Mrs. McCormick was at least entitled to a "potential retirement allowance."

For another reason, also, Mrs. McCormick was entitled to remain a member of the system. On May 6, 1958, when she asked for the return of her accumulated total deductions, she was entitled to workmen's compensation payments. The city's liability for these was redeemed by a lump sum payment in March, 1960. The amount of this payment does not appear in the record, but the board, in its brief, assumes (although it does not expressly concede) that, even as late as July 6, 1961, the period over which the lump sum was to be allocated pursuant to § 14 (1) (c), had not expired. During that period she retained by virtue of § 14 (1) (a), first paragraph, "all the rights of a member in service" until a retirement allowance should become effective for her.

Certain situations in which a member of a system may obtain return of her accumulated total deductions are listed in § 10 (4), as it appears in St. 1945, c. 658, § 1. The second sentence of § 10 (4) affirmatively authorizes certain members to be paid the amount of their accumulated total deductions. Mrs. McCormick is not one of these nor is she a person mentioned in the last sentence of § 10 (4). Because she was not one of the persons expressly entitled under § 10 (4) to a return of the accumulated deductions, Mrs. McCormick argues that she (as a member entitled to an accidental disability retirement allowance) was impliedly excluded from those who could be paid the amount of her accumulated deductions in the absence of an affirmative provision authorizing such a payment to one in her position. See Cogan v. Cambridge Retirement Sys. 294 Mass. 577, 579-581, which strongly suggests that a member of a comparable system could not withdraw from the system or withdraw his accumulated total deductions, except in accordance with a specific statutory provision.

We hold that the sections of c. 32 already mentioned impliedly prohibit the payment of their accumulated total deductions to members of retirement systems except in accordance with an express statutory authorization. Section 11 (1) authorizes such a payment only as specified in certain other sections, of which those pertinent are § 10 (4) and § 13 (2) (b). Section 10 (4), see fn. 4, supra, does not provide such authority. Section 13 (2) (a), as amended through St. 1957, c. 536, authorizes such a payment if the amount of the member's annual retirement allowance would be less than $360. Section 13 (2) (b), as so amended, authorizes such a payment if the annual retirement allowance would be less than $600, and if application therefor is filed "prior to the date the first payment of such allowance would otherwise become due." We infer that Mrs. McCormick's accidental disability retirement allowance would exceed these amounts. Even that part of the allowance based upon a pension equal to two thirds of her annual nurse's salary payable under § 7 (2) (a) (ii) from the system's pension fund, could hardly have been less than $600, wholly apart from her annuity reserve fund. See § 7 (2) (a) (i). Accordingly, upon the stipulated facts, the board had no authority on May 19, 1958, to pay Mrs. McCormick her accumulated total deductions, since she was in fact entitled to a potential accidental disability retirement allowance at the time of her application for the payment on May 6, 1958.

That the board did make such a payment was excusable error, if, as the record strongly indicates, the board had no cause to know of Mrs. McCormick's potential claim and reasonably thought that it was refunding the accumulated deductions to an employee who was resigning and who had no claim to a retirement allowance. The statute is designed to give each member specified retirement benefits in accordance with standards stated in the statute. We see nothing in the statute which prevents a member from receiving those benefits because of an honest error which can readily and fairly be corrected.

The record does not require us to treat the instrument (see fn. 1, supra), filed by Mrs. McCormick as a conscious settlement by her with the board by a release (cf. Finer v. Boston, 334 Mass. 234, 240) of a doubtful claim to a disability allowance (pension and annuity) given in exchange for the payment of her accumulated total deductions to which she would have been entitled if she had no claim to a disability allowance. We need not now consider the effect of such a conscious settlement of doubtful claims. The prescribed form, to be sure, contained language of surrender of rights and privileges under the retirement system. Authority to prescribe the form "to effectuate the purposes of" §§ 1-28, was given to the Commissioner of Insurance under § 21 (4), as appearing in St. 1945, c. 658, § 1. This authority cannot be exercised to allow repayment of accumulated total deductions to members in cases where the statute does not expressly permit such repayments. In cases of permitted payments, the language of surrender in the form may well be appropriate, but it should not prevent correction of an unauthorized, erroneous repayment where the circumstances do not indicate that the document was carrying out the intentional adjustment of a doubtful controversy.

We hold that, in the circumstances, Mrs. McCormick is not barred by the application of May 6, 1958, from applying for an accidental disability retirement allowance or from receiving such an allowance, if her application is prosecuted and allowed in usual course. The board is not precluded from accepting her tender of a refund with interest of her accumulated total deductions.

The case is remanded to the Superior Court for the entry of a final decree declaring the rights of the parties in a manner consistent with this opinion.

So ordered.