title: Fine structure of the protonephridial system in Planaria. II. Ductules, collecting ducts, and osmoregulatory cells.
mesh_terms: D000818:Animals; D006652:Histological Techniques; D008858:Microscopy, Phase-Contrast; D014419:Turbellaria / Q000166:cytology* / Q000378:metabolism; D014882:Water-Electrolyte Balance