(1) If an employee has a permanent disability in the form of the loss of a hand, arm, foot, leg or eye and subsequently has an injury arising out of and in the course of his employment which results in another permanent disability in the form of the loss of a hand, arm, foot, leg or eye, at the conclusion of payments made for the second permanent disability he shall be conclusively presumed to be totally and permanently disabled and paid compensation for total and permanent disability after subtracting the number of weeks of compensation received by the employee for both such losses. The payment of compensation under this section shall be made by the second injury fund, and shall begin at the conclusion of the payments for the second permanent disability.

    (2) Any permanently and totally disabled person as defined in this act, if such total and permanent disability arose out of and in the course of his employment, who, on and after June 25, 1955, is entitled to receive payments of workmen’s compensation in amounts per week of less than is presently provided in the workmen’s compensation schedule of benefits for permanent and total disability, and for a lesser number of weeks than the duration of such permanent and total disability, after the effective date of any amendatory act by which his disability is defined as permanent and total disability, or by which the weekly benefits for permanent and total disability are increased, shall receive weekly from the carrier on behalf of the second injury fund differential benefits equal to the difference between what he is now or shall hereafter be entitled to receive from his employer under the provisions of this act as the same was in effect at the time of his injury, and the amounts now provided for his permanent and total disability by this or any other amendatory act, with appropriate application of the provisions of section 351 to 359. Such payments shall continue after the period for which the person is otherwise entitled to compensation under this act for the duration of the permanent and total disability. Any payments so made by a carrier pursuant to this section shall be reimbursed to the carrier by the second injury fund as provided in this chapter.

    (3) Any person who prior to July 1, 1968, has been receiving or is entitled to receive benefits from the second injury fund pursuant to any prior provisions of the workmen’s compensation law shall continue to receive or be entitled to receive such benefits from such fund which shall be paid directly to him from such fund unless such payments are paid in accordance with an agreement made pursuant to section 541.

    (4) If any carrier is unable to make the payments on behalf of the fund as provided for herein, the trustees of the second injury fund may make the payments directly to the permanently and totally disabled employee.

    (5) The obligation imposed by this section on a carrier to make payments on behalf of the second injury fund shall not impose an independent liability on the carrier nor obligate the carrier to make payments on behalf of the fund if the carrier does not have a separate obligation to make payments of compensation simultaneously to the permanently and totally disabled employee.