This was accepted by J. Math. Phys. subject to a few minor revisions, but I withdrew it because of the intervening publication by the mathematician Victor Kac of the complete classification of the algebras, now called Lie superalgebras. In retrospect, the approach was so different from that of Kac that I should have published this work. Several recent papers have used similar formalisms to mine.
The results obtained here, unexpected at the time, have been confirmed by subsequent experiments and theory.