  We calculate the effects of the target mass on deep-inelastic electron
scattering on targets of spin one such as the deuteron, focusing on the novel
structure functions that enter. It is important to understand these effects
given the recent HERMES measurements of the $b_1(x,Q^2)$ structure function of
the deuteron. We also derive the spin-one analogues of the Wandzura-Wilczek
relations and discuss possible calculations in lattice QCD.
