Parabolic focal conics develop at 10-20 wt % surfactant in the two-phase lamellar-isotropic regions of various systems (SDS-hexanol-decane-water, alkylpolyglucoside APG600-fatty alcohols pentanol, hexanol, decanol, dodecanol, tetradecanol, oleyl alcohol). Extended regular quadratic two-dimensional lattices are formed in microslides (0.05-0.4 mm thickness) when only a small amount (10-15 wt %) of the isotropic phase is present. Five different focal planes can be visualized with the polarization microscope. The midplane focus gives pictures which look like primitive two-dimensional lattices of equally sized vesicle droplets. The 1:1 mixtures give irregular pattern formation. Removal of the isotropic phase by a 20 min centrifugation at 3000g leads to ordinary focal conics. Parabolic focal conics seem to be formed when the isotropic phase and the coexisting lamellar phase have comparable compositions, and this leads to the assumption that both phases should be in a near-critical state. The formation of parabolic focal conics looks more like a spinodal demixing than a crystallization process with nucleation. The very regular parabolic focal conics are transient states which change to mosaic textures, which look very similar to hexagonal fan textures, whereas polycrystalline parabolic focal conics transform to ordinary focal conics after several days or weeks.