Results of saturation magnetization measurements on both a- and b-axis single crystals of alloys of 14.5 atomic percent neodymium in gadolinium, 11.0 atomic percent praseodymium in gadolinium, and 8.3 atomic percent cerium in gadolinium are reported. In addition, saturation magnetization measurements on basal plane single crystals of the pure host gadolinium for each alloy are reported. These results are interpreted in terms of a simple vector model, which indicates that, for these alloys, the total angular momentum vectors of the light rare earth ions are aligned antiparallel to the momentum vectors of the gadolinium ions. This result tends to support the hypothesis that, due to strong spin-orbit coupling, the projection of the spin vector onto the total angular momentum vector, and not the spin vector itself, should enter into the interaction Hamiltonian; *USDOE Report Is-T-982. This work was performed under Contract W-7405-eng-82 with the U.S. Department of Energy.