The corporate powers and duties of every village so incorporated shall be vested in a board of trustees, to consist of five members, unless such town shall contain more than twenty-five hundred inhabitants, in which case such board may consist of nine members, the number to be determined by a vote of the voters of such village. The first board of trustees shall be appointed by the county commission at the time of declaring such town incorporated. If the board consists of five members the county commission shall designate two members who shall serve for terms of two years and three members who shall serve for terms of one year. If the board consists of nine members the county commission shall designate four members who shall serve for terms of two years and five members who shall serve for terms of one year. Thereafter all members shall serve for terms of two years and until their successors are elected and qualified.