Fig. 5

General anatomy of the anterior end of adult Hypania invalida, 5 μm sections, Azan-staining, light microscopic images. A. Cross-section through anterior part of inverted pharynx, see Fig. G. Short buccal tentacles situated inside the pharyngeal cavity. B. Cross-section through the posterior part of the inverted pharynx, see Fig. G. Folded pharynx located inside the oesophageal cavity associated with short tentacles. C. Cross-section through the posterior part of the oesophageal cavity, see Fig. G. Long buccal tentacles filling the whole cavity of the oesophagus. D. Close-up of a cross-section through the branchiae with two prominent blood vessels, see Fig. A. E. Close-up of the anterior region of the subepidermal ventral nerve cord and ganglionic cell somata. F. Close-up of the posterior part of the oesophagus, see Fig. C, with numerous long tentacles located inside the oesophageal cavity. G. 3D-visualization of the anterior central nervous system and stomatogastric region, long distal buccal tentacle associated with the pharynx, oesophagus omitted. Frames show area of Parafin-sections of Fig. A, B and C. H. Digital sagittal section through the 3D-visualisation of the anterior central nervous system and the short buccal tentacles located in the middle part of the pharynx. br – branchiae; brn – branchiael nerves; bv – blood vessel; cc – circumoesophageal connectives; cs – cell soma; cu – cuticle; cv – coelom cavity; dpbr – dorsal region of brain; ep – epidermis; lte – long buccal tentacles; mo – mouth opening; oe – oesophagus; pa – palae bristles; ph – pharynx; ste – short buccal tentacles; te – buccal tentacles; vnc – ventral nerve cord; vpbr – ventral region of brain