Fig. 2

a Enlargement of zone a in Fig. 1c, showing putative stem cells (blue nuclei), Müller cells (dark yellow nuclei), and differentiated lamellar cells (red nuclei). Scale bar = 5 μm. b Putative stem cell (blue nucleus surrounded by pink cytoplasm) reconstructed in three dimensions to show its concavo-convex shape. Scale bar = 2 μm. c SBSEM image of stem cell; the cytoplasm includes a mitochondrion and profiles of rough endoplasmic reticulum (arrowhead). Scale bar = 1 μm. d Chromatoid body (arrowhead) adjacent to nucleus of putative stem cell. Scale bar = 1 μm. e Nucleus and cytoplasm of Müller cells in zone a; some of these (arrowhead) appear to be penetrating from the periphery into the core of the notochord. Scale bar = 5 μm. f One of the most posterior Müller cells in (e), turned to emphasize its concavo-convex shape. Scale bar = 2 μm. g SBSEM image showing the foregoing Müller cell (top right) with conspicuously lucent nucleus and cytoplasm. Scale bar = 2 μm. h SBSEM image showing a ventral Müller cell with a mitochondrion and deep invaginations (arrowhead) of the plasma membrane within the lucent cytoplasm; the cell extends a blunt cytoplasmic projection at top left. Scale bar = 1 μm