Miss. Code § 21-5-11
The executive and administrative powers and duties in such cities shall be distributed into and among as many departments as there shall be members of the council, to be defined and designated by ordinance. The council shall, by ordinance, determine the powers and duties to be exercised and performed by each department, and shall assign the various officers and employees of the city to the appropriate department. The council shall prescribe the powers and duties of such officers and employees and make all such rules and regulations as may be necessary or proper for the efficient and economical conduct of the business of the city. The council shall, by a majority vote, designate one member of the council to be superintendent of each department of the municipal government, and shall define his powers and duties as such superintendent. Such designation may be changed whenever it shall appear that the public service may be benefited thereby unless the councilmen had been elected to head the department as hereinafter provided.
The council may, by ordinance, provide that the commissioners be designated by Post No. 1 and Post No. 2, and by ordinance define the duties which shall be performed by the commissioners elected to each post.
In the event a city with the population in excess of one hundred thousand (100,000) inhabitants or more according to the last decennial census and being governed by the commission form of government shall elect pursuant to Section 21-5-3, Mississippi Code of 1972, to have additional councilmen, the council may, by ordinance, provide that the councilmen or commissioners be designated by post numbers, said posts to be numbered consecutively from one (1) upward, and by ordinance define the duties which shall be performed by the commissioners elected to each post.
Miss. Code § 21-5-11