Figure 4 in Redescription of Lineus acutifrons Southern, 1913 (Nemertea: Pilidiophora) and comments on its phylogenetic position

Figure 4. Lineus acutifrons. (A) Transverse section showing the two lateral cephalic lacunae; (B) transverse section at brain level showing ventral lacuna; (C) transverse section at brain level showing two ventral lacunae; (D) transverse section at brain level showing four lacunae; (E) longitudinal section of the cephalic slit showing the aperture of the ciliated canal; glandular area with long cilia are marked with arrows; (F) longitudinal section at the tip of the head. Scale bars A–F: 100 µm. Abbreviations: ao, apical organ; cl, cephalic lacunae; dc, dorsal commissure; ll, lateral lacunae; mvl, mid-ventral lacuna; pp, proboscis pore; r, rhynchocoel; vl, ventral lacuna.