Fig. 8. Whole mounts showing the distribution of NADPH diaphorase staining in autozooid polyps of R. koellikeri. (A,B) Overview at two different focal planes of the upper part of a polyp where the base of tentacles is heavily populated by brown endosymbiotic algae. Note that focus is on staining of the oral disc in A, and on aboral tentacle and body column staining in B where bundles of tentacle neurites (arrows) extend to the body column (arrowheads). (C) Enlarged view of an oral disc region corresponding to the rectangle in A. Note clusters of cell somata at the margin (arrowheads) and meshwork of cell processes throughout the oral disc (arrow). (D) Enlarged view of a tentacle area corresponding to the rectangle in B. Note neurites running parallel to each other and cell somata (arrows) at the tentacle/body column interface. (E) Two bands of basiectodermal stained cell somata flank a tentacle on the aboral side. Processes from these cell bands extend towards the endodermal layer of the tentacle (arrow) and in the septum endoderm of the column (arrowhead). (F) Bands of stained neurites on the oral side of a tentacle (arrows) appear to merge into the similarly stained oral disk nerve-net. (G) Enlarged view of stained basiectodermal cell somata with an apical process (arrowheads). Neuritic processes from these cells (between arrows) extend towards the ectoderm/mesoglea interface. Scale bars: 200 µm (A,B), 25 µm (C), 30 µm (D), 80 µm (E), 50 µm (F) and 15 µm (G).