The county clerk of each county or any commissioned officer of the United States Army, Navy or Marine Corps may administer the oath of office and allegiance to every person chosen or appointed as a coroner in or for said county; provided, that when said oaths of office and allegiance have been administered by a commissioned officer there shall be a recital that he is such commissioned officer including a recital of his rank and official designation as such and that the person taking such oath is in the military or naval service of the United States.
N.J.S. § 41:2-11