This report provides evidence for the appearance of the plasma mantle at low latitudes, ZGSM~0. A detailed analysis of Geotail observations on January 20, 1996, clarifies the characteristics of the plasma flow in the low-latitude mantle. The tailward flow speed in the mantle is 200--400 km s-1, smaller than the flow speed (≳400 km s-1) in the adjacent magnetosheath, and flow and field perturbations satisfy the criteria for a rotational discontinuity. The velocity component parallel to the mantle magnetic field line is positively correlated with the ion number density, consistent with a boundary layer interpretation. The component of the velocity perpendicular to the magnetic field lines is predominantly poleward at speeds up to 150 km s-1. This poleward convection can be interpreted as being driven by a J¿B force operating on the field lines. ¿ 2001 American Geophysical Union