The petitioners appeal from an order for judgment dismissing a petition for a writ of mandamus to compel the respondent board inter alla to certify an alleged referendum petition. The alleged referendum petition, filed with the city clerk on September 13, 1966, was directed to an order passed by the city council on August 15, 1966. Assuming that what was filed by the petitioners with the respondent city clerk qualified as a referendum petition, it was not filed within twenty days following the passage of the protested measure. See G. L. c. 43, § 42. The *748petition was not in terms directed to a later order passed by the city council on August 24, 1966, the subject matter of which was distinct from that of the earlier order.

Order for judgment affirmed.