function save_mouthgt( output2d_file, m )
  
  if nargin < 2
    error( [ mfilename ' needs 2 input arguments.' ] );
  end
  
  fid = fopen( output2d_file, 'wt' );
  if fid < 0
    error( [ mfilename ' could not write-open "' output2d_file '"' ] );
  else
    fprintf( fid,'%4d %4d %4.1f %10.4f %10.4f\n',m.');
    fclose( fid );
  end