Before revision: In both examples it should be noted that the proportions of the extraordinary wavefront expanding from a point source in the crystal are inverse to those of the index surface, because the refractive index is inversely proportional to the normal velocity of the wavefront.
After revision: In both examples the proportions of the extraordinary wavefront expanding from a point source in the crystal are inverse to those of the index surface, because the refractive index is inversely proportional to the normal velocity of the wavefront.