Gold islands have been grown epitaxially on an MgO substrate in a cube-cube orientation. Applying the O-lattice theory, misfit dislocations are predicted to form a square network of edge-dislocations spaced 9.9 nm apart, and with a Burgers vector of 1/2.a . Bright-field and weak-beam images did not reveal the presence of such dislocations. Indirectly, however, the creation of misfit dislocations is shown to manifest itself through a slight rotational distortion of the islands, and the interface can be regarded as consisting of coherent domains bounded by incoherent bands