Mesogleal amoebocytes of free-living Polypodium hydriforme have been studied with transmission electron
microscope. The amoebocytes have numerous processes and contain cytoplasmic vacuoles with fibrous material of different density.
The phenomenon of cell death (apoptosis) of mesogleal amoebocytes is described. Chromatin of dying cells becomes condensed
forming picnotic "caps" in the nucleus. No mitotic cells were encountered among mesogleal amoebocytes. The origin and functions
of mesogleal amoebocytes of P. hydriforme are discussed.
