  A non standard super extensions of the Poincare algebra (S-algebra [1,2]),
which seems to be relevant for construction of various D=11 models, are
studied. We present two examples of actions for point-like dynamical systems,
which are invariant under off-shell closed realization of the S-algebra as well
as under local fermionic $\kappa$-symmetry. On this ground, an explicit form of
the S-algebra is advocated.
