We construct a new extension of the Poincar superalgebra in eleven dimensions which contains super one-, two-and five-form charges. The latter two are associated with the supermembrane and the superfivebrane of M-theory. Using the Maurer-Cartan equations of this algebra, we construct closed super seven-forms in a number of ways. The pull-back of the corresponding super six-forms are candidate superfivebrane Wess-Zumino terms, which are manifestly supersymmetric, and contain coordinates associated with the new charges.
