Data measured in the magnetosheath by the Geotail satellite are used to test for the existence of a proportional relation between the temporal changes in magnetic field, DeltaB, and the temporal changes in plasma. velocity, DeltaV. We have compared the ratio \DeltaV/DeltaB\ with that which would be anticipated from magneto-hydrodynamic wave theory. When the plasma's beta exceeds 1, the ratio often significantly differs from that expected from any wave mode in isotropic plasmas. The existence of anisotropies in plasma distribution functions and consequent modifications of \DeltaV/DeltaB\ is strongly suggested. Under the assumption that the modifications of \DeltaV/DeltaB\ are predominantly caused by such temperature anisotropies; beta(parallel to)/beta(perpendicular to) is evaluated over the range from 1 to 3. These anisotropies of plasma temperature may be caused by the adiabatic expansion of magnetic flux tubes in the magnetosheath. (C) 2002 Elsevier Science Ltd. All rights reserved.