Fig. 2. Whole-mount scanning electron micrographs (SEM) and transmission electron micrographs (TEM) showing the overall external and internal anatomy of the three ciliary subtypes of a stage E28 embryo. (A) Left lateral view SEM showing the position of the scattered single ciliary cells (sc) relative to the dorsolateral ciliary bands (dl) and pedal ciliary band (p). The shell (sh) and mouth (mo) are also shown. Scale bar, 25 µm. (B) SEM showing the configuration and density of cilia of a dorsolateral ciliary cell. Scale bar, 1 µm. (C) SEM showing the configuration and density of cilia of a pedal ciliary cell. Scale bar, 1 µm. (D) TEM of a dorsolateral ciliary cell showing numerous mitochondria (mi) and the nucleus (n). Electron-translucent regions are designated by an arrow. The cilia (c) with basal body (bb), ciliary rootlet (cr) and accessory ciliary rootlet (acr) are also shown. Scale bar, 1 µm. (E) SEM showing the configuration and density of cilia of one of the scattered single ciliated cells. Scale bar, 1 µm. (F) TEM of a scattered single ciliated cell showing the cytoplasm. Note the cilia (c) with basal body (bb), ciliary rootlet (cr), less prominent mitochondria (mi) and the nucleus (n). Scale bar, 1 µm. Inset: cross section through a cilium showing the (9x2)+2 doublets of microtubules. Scale bar, 0.5 mm.