Fig. 4C and D rep- resents the predominant ribbon-like thickenings. Such ribbon-like thickenings consist of several helices which are closely packed and equally spaced in the axial direction.
Fig. 4C and D rep- resents the predominant ribbon-like thickenings. Such ribbon-likethickenings consist of several helices which are closely packed and equally spaced in the axial direction.