Cell and Tissue Research

, Volume 199, Issue 2, pp 319–338

The fine structure of the hypostome and mouth of hydra

II. Transmission electron microscopy
  • Richard L. Wood


The normal morphology of the hypostome and mouth of hydra were examined by transmission electron microscopy with conventional thin sections and freeze-fracture replicas. Myonemes of the hypostome are small in diameter, have gap and intermediate-type cell junctions within each epithelial layer and are associated with the opposite epithelial layer by transmesogleal processes and gap junctions. Nematocysts and sensory cells are aggregated in the circumoral region. The fine structure of adherent flagella arising from gastrodermal gland cells, and the transition region at the mouth between epidermis and gastrodermis are described in detail for the first time. The possible functional significance of the findings is discussed.

Key words

Hydra Hypostome Myonemes Flagella Freeze-fracture 


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Copyright information

© Springer-Verlag 1979

Authors and Affiliations

  • Richard L. Wood
    • 1
  1. 1.Department of AnatomyUniversity of Southern California School of MedicineLos AngelesUSA

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