Fig. 8

24-h larva. 3-D reconstructions based on SBSEM sequences. a Left-side structures from lateral viewpoint. The subectodermal basal lamina (indicated by parallel black traces) is interrupted (as a lateral window) over the oral mesoderm cells. Within Hatschek’s nephridium (rendered semitransparent) the cell nuclei (gold) are indicated as are several flagellar/microvillar processes (blue). The arrow and arrowhead are explained in the caption for Fig. 9. b Left-side structures from a medial viewpoint. The nuclei (blue) of the oral mesoderm cells are visible through a medial window in the subendodermal basal lamina. The asterisk marks an interruption in the basal lamina where Hatschek’s nephridium opens into the pharyngeal lumen. c View of left-side structures from the posterior showing that a basal lamina (parallel black traces) bounds Hatschek’s nephridium posteriorly but does not intervene between the oral mesoderm cells and the lateral plate mesoderm (toward viewer). d Similar view to c showing ectoderm cells (various colors), nuclei (blue) of the oral mesoderm, and nuclei (purple) of the pharyngeal endoderm. e Inner surface of the ectoderm (brown) viewed from anteriorly; dorsal and ventral are toward the upper right and lower left, respectively; three selected lateral cells of the oral mesoderm are shown in yellow. f Inner surface of the ectoderm (brown) viewed from posteriorly; dorsal and ventral are toward the upper right and lower left, respectively; for selected oral mesoderm cells, a lateral cell is yellow, a dorsal and a ventral cell are red, and three medial cells are green. ect, ectoderm; fls, first left somite; fmp, flagellar/microvillar process; Hld, Hatschek’s left diverticulum; Hn, Hatschek’s nephridium; no, notochord; pe, pharyngeal endoderm; om, oral mesoderm; sls, second left somite. All scale bars = 5 μm