Ultrastructure of the cuticle in the anterior chamber and the papillate region. A The cuticle in the anterior chamber consists of thin epicuticle (EPI) and thick procuticle (PRO) with distinct sublayers. Between the epicuticule and the procuticle, a thin layer of intermediate electron density is present (arrow) B Cuticle in the papillate region consists of epicuticle (EPI) which is proportionally thicker according to the procuticle (PRO). Procuticle sublayers are less pronounced than in the anterior chamber. Between the epicuticle and the procuticle a thin layer of intermediate electron density is present (arrow) C, D The outer part of the epicuticle (EPI) in the anterior chamber (C) and in the papillate region (D) is three-layered (arrow) and covered with a fuzzy layer (arrowhead) E Procuticle (PRO) in the papillate region can be of approximately the same thickness as epicuticle (EPI) and without apparent sublayers.