Left: Sérsic index compared to pitch angle for a subsample of galaxies used in this work. The black triangles represent regular (non-barred) spiral galaxies. Red hexagons are galaxies with morphological classifications as weak bars. Finally, blue squares are barred galaxies. Right: a comparison of log(Mass) from the literature with the log(Sérsic-index-derived mass) using the relationship of Graham & Driver (2007). The solid line through the data represents the 1:1 line. Note that non-barred galaxies have much less scatter about the 1:1 line than either variety of barred galaxy. The scatter for the total sample is ~0.60 dex, but is only 0.15 dex for spiral galaxies without bars, 0.73 and 0.72 dex for barred and weakly barred galaxies. No limits are used in this right panel, and hence there are fewer points than in the panel on the left.