Fig. 8.

Magelona mirabilis, semi-thin section and ultrastructure. a: semithin section (1 μm) Toluidine blue; B,C: ultrathin sections (70 nm). A: The neurites (ne) of the nervous system are directly associated with the epidermal basal lamina (bl). Somata (so) of the neurons are located in the periphery of the neuropil. Radial glia cells which contain intermediate filaments (if) are attached to the basal lamina and run through the neuropil between the cells of the epidermis (ep). cu: cuticle. b: higher magnification of rectangle in A. The intermediate filaments (if) are attached by hemidesmosomes (hd) to the adjacent glia cells. Somata are located in the periphery of the neuropil. Neurites (ne) are differently orientated and pigment (pi) containing cells overlie the neuropil layer. c: higher magnification of rectangle in A. The neurites (ne) of the brain are located directly above the basal lamina (bl) of the epidermis. Pigment (pi) containing cells are less abundant than in the region towards the cuticle