Black hole mass vs. pitch angle for all spiral galaxies with directly measured black hole masses available. The best linear fit to this data is illustrated and gives the following relation log ( M _BH/ M _☉) = (8.21 ± 0.16) − (0.062 ± 0.009) P. The fit has a reduced χ ² = 4.68 with a scatter of 0.38 dex. Black hole masses measured using stellar and gas dynamics techniques are labeled with black ×'s (10 points), reverberation mapping masses with red triangles (12 points), and maser measurements with blue squares (12 points).