Megadenus holothuricola Rosén, 1910 A adults immersed in the main tube of the respiratory tree B, C two adults showing the mottled skin of the respiratory tree and the pseudopallium covering shell; proboscis slightly rolled, and another adult stretched to the maximum D cephalic view, 40× E two egg capsules, L = 2 mm F view of the distal part of an adult proboscis. Scale bars: 1.2 mm (A); 2.3 mm (B); 1.65 mm (C); 0.8 mm (D); 0.6 mm (E); 0.5 mm (F). Abbreviations: e: eyes; eg: egg capsules; p: proboscis; pg: pedal gland; pp: pseudopallium; rt: respiratory tree; s: shell; t: tentacle.