X − Y (upper panel) and X − Z (lower plane) projection of the true and probable clusters in our sample (open circles). The red squares enclose the youngest clusters in our list (see Table 4). The thick gray lines in the upper panel show the trace of the Perseus and Carina arms according to Vallée (2005). The position of the Sun is shown by a blue crossed circle. The dashed line in the lower panel depicts the Galactic equator.