| Abstract: | SYNOPSIS. Ichthyosporidium sp. Schwartz, 1963, apparently identical with the type species, I. giganteum (Thélohan, 1895) Swarczewsky, 1914, was studied with the electron microscope. Only late stages, a mature cyst containing sporulation stages and a cyst in the terminal (necrotic) stage were observed. The cyst, originating from host tissue, is a highly organized structure that is integrated with the surrounding connective tissue by means of numerous conspicuous processes. It is interpreted as essentially a manifestation of a defensive reaction of the host that is elicited by the parasite and then used to its advantage. Eventually the cyst dies and disintegrates. This type of cyst, peculiar among those associated with microsporidia, may be regarded as a distinctive character of the poorly defined genus Ichthyosporidium. Other observations let to an hypothesis which reconciles several different views regarding the identity of the Golgi complex. According to this new interpretation, these different views concern different aspects af the total complex. When all such views are integrated, a “classical Golgi” can be recognized in the presporoblastic stages and the “primitive Golgi” concept disappears. This “classical Golgi” then becomes highly modified during spore morphogenesis, giving rise to many of the internal organelles that are peculiar to the spore. |
