title: The ultrastructure of the zymogen cells in Hydra viridis.
mesh_terms: D003063:Cnidaria / Q000166:cytology*; D004721:Endoplasmic Reticulum; D004792:Enzyme Precursors / Q000378:metabolism; D006652:Histological Techniques; D008854:Microscopy, Electron
chemical_list: D004792:Enzyme Precursors