Phyllidia ocellata Cuvier. Images showing a selection of the histological slides. A. Mouth leading to non-glandular oral tube and lobed glandular pouch (arrows); B. Oral glands (GOT) with inserting retractor muscle and part of the nerve ring. Note the transition from pharynx into oesophagus indicated with an arrow; note the different glandular areas of the GOT, especially the violet-stained lappets (arrowheads); C. Gonad with spermatogonia and mature sperm (arrows); D. Cross section through genital system with receptaculum seminis and ampulla; insertion of retractor muscle at the peritoneal wall and dorsoventral muscle bundles in lateral notum (star); E. Penis with spines (arrow) in penial sheath. Abbreviations: amp ampulla, got glandular oral tube, oe oesophagus, ot oral tube, mo mouth, nigl nidamental glands, peg pedal ganglia, ph pharynx, plg pleural ganglia, pes penial sheath, rem retractor muscle, spg spermatogonia, spi spicules, vot ventral part of oral tube without glands.