2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/54442We discuss an extension of the super-Poincaré algebra in $D=11$ which includes an extra fermionic charge and super two-form charges. We give a geometrical reformulation of the $D=11$ supermembrane action which is manifestly invariant under the extended super-Poincaré transformations. Using the same set of transformations, we also reformulate a superstring action in $D=11$, considered sometime ago by Curtright. While this paper is primarily a review of a recent work by Bergshoeff and the author, it does contain some new results.11 pages, LaTex, Contribution to the Leuven Workshop, July 1995High Energy Physics - Theorytext