Figure 10

Transmission electron micrographs of ultrathin sections of a 10 to 16 days posthatching larva of Wirenia argentea . A: Part of a cross section through the middle part showing the pair of ventral neurite bundles (arrows) and a ventromedian neurite bundle (arrowhead) belonging to the ventromedian nerve plexus; scale bar equals 10 μm. B: Detail from A showing one of the ventral neurite bundles; scale bar equals 2 μm. C: Detail from A showing the ventromedian neurite bundle belonging to the ventromedian nerve plexus; scale bar equals 2 μm. D: Detail from a cross section through the middle part somewhat more posterior than in A, showing two neurite bundles of the ventromedian nerve plexus, one in cross section (arrowhead) and one in oblique section (double arrowhead), emphasizing the plexus-like character of this fifth concentration of nervous material (compare also Figures 5D, 8A-C and 9A-C); scale bar equals 1 μm. Abbreviations: f, foot; mg, midgut anlage.