Fine structure of early previtallogenic oocytes in Mugil (Liza) auratus Risso, 1810 (Teleostei, Mugilidae)

Sequential cytological events at the onset of previtellogenesis were studied in oocytes from 12 micrometer to 70 micrometer in diameter of golden grey mullet. The main cytological changes observed (increase in size of cell, nucleus, nucleolus and increase in number of nucleoli, RNP particles, "nuage" and mitochondria) provide evidence for important synthetic processes in an early preparatory phase of oocyte development. Somatic cells (pre-follicel, follicle and thecal) are also described.