Velocity-channel maps of the CO(2–1) line emission in the central 400′′ × 400′′ area of the IRC +10 216 envelope, observed with the SMA at a spatial resolution of 3.7′′ × 3.0′′ (HPBW, PA = –51). The spectra have been binned to a resolution of 2.1 km s^-1; velocities are relative to the LSR; the star systemic velocity is V_∗ = −26.5 km s^-1; velocities more positive or more negative correspond to the rear and front parts of the envelope, respectively. The lack of visibilities <6 m carves a negative bowl and black areas at the center of the maps (see text).