The decylammonium chloride (DACl), KCl and D2O system forms two phases(Nc+Nd) in the nematic range. The Nd phase was ca. 15% by volume and exhibited extinct appearance. From conoscopic measurements it was inferred that the optical axis of the Nd phase was tilted. The lamellar phase of the DACl-KCl-D2O system as well as the lamellar phase obtained by adding phosphoric acid decylester/phosphoric acid (PDE/H3PO4) showed the following phase sequence: [figure omitted] isotropic The line shapes of 31P NMR of PDE/H3PO4 were found to be sensitive to micelle size and dynamics occuring in the lyotropic system, but they do not differentiate between different micelle shapes. © 1995, Taylor & Francis Group, LLC. All rights reserved.