Rodriguez-Moldes, M. I., Anadbn, R. 1988. Ultrastructural study of the evolution of globules in coronet cells of the saccus vasculosus of an elasmobranch (Scyliorhinus canicula L.), with some observations on cerebrospinal fluid-contacting neurons. (Departamento de Biologia Fundamental, Universidad de Santiago de Compostela, Spain.)-Acta ZOO^. (Stockh.) 69, 217-224.The luminal surface of the coronet cells of the dogfish saccus vasculosus has been studied by scanning and transmission electron microscopy. Most of these cells have a mulberrylike structure composed of 25-35 closely arranged globules originated from ciliary stalks. In adult dogfish some coronet cells have globules either shedding or in different phases of formation from cilia. We report here the description of dogfish coronet cells and the discussion on a putative globule formation cycle. Cerebrospinal fluid (CSF) contacting neurons of the dogfish saccus vasculosus were also described.