Section 12. The first meeting of the corporation shall be held within six months after the execution of the articles of organization. If the directors of the corporation have been previously chosen in anticipation of its organization, or in connection with a plan for preliminary organization, or in accordance with contracts made in anticipation of such organization, such choice of directors shall be ratified at said meeting. Elections of directors shall thereafter be governed by section forty-seven of chapter one hundred and fifty-six B, except as provided in the following section.