Members who on January 1, 1976, are in state service positions according to former Section 13948 as it read on December 31, 1975, or who are employees of the Trustees of the California State University, may elect in writing prior to July 1, 1976, not to continue as members of this system and to transfer membership to the Public Employees’ Retirement System. Failure to execute and file the election, which shall be received in the office of this system by the close of business on June 30, 1976, shall be deemed a decision to remain a member of the plan.