Forebody innervation in <i>Paradiplozoon homoion</i> adults.

<p><b>A)</b> Tegumentary ridges and uniciliated sensory structures. SEM. <b>B)</b> Micrograph revealing the distribution of uniciliated sensory structures. CLSM, IFA-FITC. <b>C-D)</b> Longitudinal and transverse connective nerve cords. CLSM, IFA-FITC. <b>E)</b> Detail of the sensory structure, with visible cilium anchoring. SEM. <b>F-G)</b> Arrangement of uniciliated sensory structures and peripheral nerve fibres within the tegumentary ridges. CLSM, IFA-FITC (F) and IFA-FITC/phalloidin-TRITC (G). <b>H)</b> Superficial distribution of uniciliated structures, a view comparable with B). The inset to the right shows a detail of two sensory structures from H) (<i>encircled</i>), while the left inset shows the circular rim rich in F-actin only; both views are magnified five times. CLSM, IFA-FITC/phalloidin-TRITC. <b>A</b>, <b>C</b>, <b>D</b>, <b>F</b> and <b>G</b> are composite views created by flattening a series of optical sections, while <b>H</b> represents a single median optical section. <i>asterisk</i>–cilium, <i>black arrowhead</i>–circular rim, <i>black arrows</i>—longitudinal nerve cords, <i>mo–</i>mouth opening, <i>white arrowheads</i>–uniciliated sensory structures, <i>white arrows</i>–transverse connective cords.