  An $SO(9,1)$ invariant formulation of an 11-dimensional supermembrane is
presented by combining an $SO(10,1)$ invariant treatment of reparametrization
symmetry with an $SO(9,1)$ invariant $\theta_{R} = 0$ gauge of
$\kappa$-symmetry. The Lagrangian thus defined consists of polynomials in
dynamical variables (up to quartic terms in $X^{\mu}$ and up to the eighth
power in $\theta$), and reparametrization BRST symmetry is manifest. The area
preserving diffeomorphism is consistently incorporated and the area preserving
gauge symmetry is made explicit. The $SO(9,1)$ invariant theory contains terms
which cannot be induced by a naive dimensional reduction of higher dimensional
supersymmetric Yang-Mills theory. The $SO(9,1)$ invariant Hamiltonian and the
generator of area preserving diffeomorphism together with the supercharge are
matrix regularized by applying the standard procedure. As an application of the
present formulation, we evaluate the possible central charges in superalgebra
both in path integral and in canonical (Dirac) formalism, and we find only the
two-form charge $[X^\mu, X^\nu]$.
