Integrated intensity contours of the ¹²CO emission clouds every 1.0 km s^-1 superimposed on the GLIMPSE 8.0 μm grayscale. The lowest contour level for each velocity panel from −14.5 to −6.5 km s^-1 is 1.59, 1.37, 1.80, 2.24, 1.96, 2.19, 2.80, 1.22, and 0.95 K km s^-1, respectively; the level increment of each panel is equal to the corresponding value of the lowest contour level. The blue, green, and red contours indicate the blueshifted, systematic, and redshifted velocities, respectively. The white ellipse indicates the position of bubble N131.