  An open string in four dimensions is supplemented by forty four Majorana
fermions. The fermions are grouped in such a way that the resulting action is
supersymmetric. The super-Virasoro algebra is constructed and closed by the use
of Jacobi identity. The tachyonic ground state decouples from the physical
states. After a GSO projection, the resulting physical mass spectrum is shown
to be $\alpha' M_n^2 =n$ where $n=0, 1, 2, ...$. There are fermions and bosons
in each mass level. The internal symmetry group of the string breaks to $SU(3)
\times SU(2)\times U(1) \times U(1)$.
