2015 New York Laws
ACG - Alternative County Government
Article 3 - (Alternative County Government) BOARD OF SUPERVISORS
100 - Board of supervisors.

  100. Board of supervisors. 1. A county adopting an alternative form
  of county government shall continue to have a board of supervisors.  The
  supervisors of the several cities and towns in the county, when lawfully
  convened, shall constitute the board of supervisors.
2.  If  the  petition or resolution for the adoption of an alternative
  form of county government or  for  the  modification  or  change  of  an
  alternative  form  previously adopted shall so provide and the adoption,
  modification or change  shall  be  approved  by  the  voters  as  herein
  provided,  the  members  of  the  common  council  or  other legislative
  governing body of each city within the county shall serve as the members
  of the county  board  of  supervisors  representing  such  city  and  no
  separate city supervisors shall be elected. In such case each city shall
  continue  to  have the number of votes on the board of supervisors which
  it would have had if this option had not been exercised and the votes of
  each city shall be divided equally among the members  representing  such
  city.