Figure 9. (A–B) Transverse sections through the frontal organ of Pantinonemertes californiensis; (C–I) Prosadenoporus spectaculum comb. nov.: (C–F) a series of transverse sections through the tip of the head showing frontal organ twisting; lateral acidophilic regions of the frontal organ marked with arrowheads; (G) transverse section through the cerebral ganglia showing two neurochord cells (circled, insert); (H) transverse section through the proboscis insertion and anterior portion of cerebral ganglia showing contracted proboscis insertion muscles; (I) transverse section through the posterior region of brain showing beginning of the lateral nerve cords (asterisks) which appear sectioned longitudinally, presumably because of the severe contraction of the specimen during fixation. Notes: bgl, basophilic cephalic glands; cg, cerebral ganglia; fo, frontal organ; ogl, orange-G cephalic glands; vc, ventral brain commissure. Scales: (A–F), 50 mm; (G), 100 mm (insert, 50 mm); (H–I), 200 mm.