Section 42. In any city or town, except Boston, which accepted chapter four hundred and ninety-eight of the acts of nineteen hundred and eight, the pension fund established for the retirement of teachers in the public schools shall be derived from such revenues as may be assigned thereto by the city council of a city or by direct appropriation by a town. The treasurer of the city or town shall be the custodian of the fund and shall make monthly payments therefrom to such persons and of such amounts as shall be certified to him by the school committee.