§ 60. Directors; terms; election; duties. Except as otherwise provided in this chapter, the board of directors shall be divided, as nearly equally as practicable, into three classes. At the first annual meeting, the members shall elect from among themselves a director or directors of the first class for a term of one year; of the second class for a term of two years; and of the third class for a term of three years. At the expiration of the respective terms, successors shall be elected for terms of three years. Successor directors of corporations to which this chapter applies, which were formed under the stock corporation law prior to January first, nineteen hundred fifty-four, need not be members.