All eligible officers and employees of the Supreme Court, except the Justices, shall be subject to a merit system of personnel administration as promulgated by the Supreme Court, under which all such officers and employees shall be selected on a basis of merit, fitness, and efficiency. All such officers and employees are authorized to become members of the retirement system. All contributions required by this chapter shall be paid from funds appropriated for the operation of the Supreme Court and all such payments shall be in addition to the regular compensation allowed to such officers and employees.