[Classification of types of oogenesis]

The classification of the types of oogeneses by Korschelt and Heider is discussed in the light of the modern data on ultrastructural, cytochemical and biochemical patterns of differentiating oocytes. A conclusion is drawn that this classification does not reflect the diversity of sources and mechanisms of the accumulation of substances in the oocyte. The author suggests to classify the types of oogenesis on the basis of behaviour of the nuclear structures in the oocyte and their participation in synthesis of RNAs passing in the ooplasm.