  A string in four dimensions is constructed by supplementing it with forty
four Majorana fermions. The central charge is 26. 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. GSO projections are necessary
for proving modular invariance and space-time supersymmetry is shown to exist
for modes of zero mass. The symmetry group of the model desends to the low
energy group SU(3)x SU(2)x U(1)x U(1).
