Morphology, histochemistry and ultrahistochemistry of special verrucose formations in daughter sporocyst of Eurytrema pancreaticum.

Verrucose formations were found on the surface of fully developed sporocysts of E. pancreaticum Janson, 1889 at the site where the attenuated proboscis-like anterior portion widens into the posterior portion. Under these verrucose formations is always a group of gland cells. Their narrowed processes pass at a common site through the muscle layer and above this layer again slightly widen and project above the neighbouring tegument. The tegument of the verrucose formation differs from the neighbouring tegument of the sporocyst. In the cytoplasm of the gland cells there are large, spherical membrane-bound bodies containing proteins with tryptophan, tyrosine and SH groups. These bodies do not have any activity of alkaline phosphatase, acid phosphatase or nonspecific esterase. Besides these protein bodies the perinuclear cytoplasm is filled with beta glycogen particles and many cisternae of endoplasmic reticulum. The processes of these cells contain thick fibriles. The verrucose formations with the gland cells seem to serve for attachement and lysis. This function is applied not only during the development of the sporocyst, but also during its release from the site of location and penetration through the snail tissue.