For the performance of the duties relating to the enrollment of electors on enrollment lists, each registrar and deputy registrar actually engaged therein, and each town clerk not upon a salary, shall receive such reasonable compensation and expenses from the town for which the enrollment is made as are approved by the selectmen thereof and, from the city or borough for which the enrollment is made, such sums as are approved by its common council or warden or burgesses or, where town and city governments are consolidated, such sums as are approved by the common council of such city.