| The aims of this paper have been (a) to characterize marginal ommatidia from different eyeregions through a detailed description of their distinct ultrastructural features in three different size-classes ofL. exotica, and (b) to compare microanatomical characteristics of the marginal ommatidia with those of ommatidia of the same eye, but located further centrally. On the basis of transverse as well as longitudinal sections we conclude that new ommatidia are added from a crescentic dorso-anterio-ventral edge of the eye and that maturing ommatidia go through a sequence in which originally the nuclei of cone -, pigment-, and retinula cells are arranged in three separate layers. At the beginning of the microvillar development, the organization of the... |
