  Studied are the composition series of the standard Whittaker (g,K)-modules.
For a generic infinitesimal character, the structures of these modules are
completely understood, but if the infinitesimal character is integral, then
there are not so many cases in which the structures of them are known. In this
paper, as an example of the integral case, we determine the socle filtrations
of the standard Whittaker (g,K)-modules when G is the group Spin(r,1) and the
infinitesimal character is regular integral.
