Mass. Gen. Laws ch. 51 § 63
After the biennial state election in nineteen hundred and forty-four, and in every tenth year thereafter for the purpose of furnishing the information necessary for a new division of a city into wards and voting precincts and of a town of twelve thousand inhabitants or over, which has been divided into voting precincts, into new voting precincts, the registrars shall deliver to the clerk of each city and of each such town, on or before the first Tuesday after the said election, a list of all voters therein who were registered for such election, which shall be so arranged as to show the number of voters residing in each ward or in each precinct, as the case may be, by streets. The registrars shall likewise in any other year, upon the request of the aldermen in cities or of the selectmen in such towns, furnish, for the purpose of dividing a ward into voting precincts or, unless otherwise prohibited by law, of dividing any such town into new voting precincts, a list of the voters of any ward in a city or of any precinct in such town, arranged as aforesaid.
Mass. Gen. Laws ch. 51, § 63