The structure of the mature oocyte and zygote of Corynosoma semerme (Acanthocephala)

Abstract

SummaryObservations made with the transmission electron microscope are described from the free ovaries of sexually mature female Corynosoma semerme (Palaeacanthocephala) from the ringed seal (Pusa hispida). The structure of the mature ovaries consists of a supporting syncytium, oogonial cells and tissue and appears to be basically similar to that already described for 4 other species of Acanthocephala representing the 3 orders of the phylum. A comparison has been made between the organization of the cytoplasm of the mature oocyte and the zygote with reference to the consequences of fertilization. A detailed description is presented of the heterogeneous inclusions that are observed in the cytoplasm of the mature oocyte but not in the zygote. The fate and possible function of the components of these inclusions is discussed.