Any member may withdraw the total sum, without interest, which he has paid into the fund. In order to become eligible to rejoin the fund and to receive any benefits under this chapter after such withdrawal, he must repay the entire amount which he has withdrawn, plus interest at 6 percent per annum. A member shall not receive credit for any service after such withdrawal unless he pays the dues which he would have paid had he been a member of the fund during such period of service, plus interest on such amounts at 6 percent per annum. If any clerk dies before being retired, the total amount, without interest, which has been paid by him into the fund shall be paid to his estate. If, after retiring, any clerk should die without leaving a surviving spouse and without having received the amount in benefits equal to the amount which he had paid into the fund, the difference, without interest, shall be paid to his estate. If after retiring, any clerk should die leaving a surviving spouse and such surviving spouse should thereafter die without having received the amount of benefits equal to the amount which had been paid into the fund less the amount received by such clerk before his death, the difference, without interest, shall be paid to his estate.