Let X be an N-manifold
of constant sectional curvature. A class of minimal surfaces in X, called
exceptional minimal surfaces, will be defined in terms of the structure of their
normal bundles. It will be shown that these surfaces can be characterized
intrinsically in a way that generalizes the Ricci condition for minimal surfaces in
Euclidean 3-space. It will also be shown that these surfaces are rigid when N is
even and belong to 1-parameter families of isometric surfaces when N is
odd.