The collection of members' contributions shall be as follows:
(1) Each employer shall cause to be deducted on each and every payroll of a member for each and every payroll period subsequent to the date of establishment of the retirement system the contributions payable by such member, as provided in this Chapter. Each employer shall certify to the treasurer of said employer on each and every payroll a statement as vouchers for the amount so deducted.
(2) The treasurer, or other officer authorized to issue warrants, of each employer, on the authority from the employer, shall make deductions from salaries of members as provided in this Chapter, and shall transmit monthly the amount specified to be deducted to the director of the board of trustees. The director of the board of trustees after making a record of all such receipts shall deposit them with the state treasurer for use according to the provisions of this Chapter, or in a bank or banks selected by the state treasurer and approved by the board of trustees.