Bonds may be issued in the total amount of all assessments in amounts of less than $25.00 which are unpaid at such time, to mature at the same time as the maturity of the first series of such serial bonds, and which assessments shall become due and payable at the same time as that portion of the larger assessments which shall have been collected for the payment of the first series of the serial bonds and the interest thereon.
(Prior code App. A, § 331)