Dr. Holló Ferenc - Dr. Murai Éva szerk.: Parasitologia Hungarica 5. (Budapest, 1972)
emitting very fine fibres to the apical end and to the fibrous mass . The excretory organ /protonephridium/ of the miracidium consists of a pair of lateral flame cells and ducts connecting with it. The flame cells lie on the border of the 2nd and 3rd cell rows, varying in size from 10 to 13x3 /a, / figs. 4 and 10/. Ducts connecting with the flame cells pass posteriorad initially, beyond the secretory pore, then curve anteriorad and,in the middle of the 2nd cell row, form several loops, extend caudal, and lead into the secretory pore / figs . _4_ and 12/. The pores open laterally between the third and fourth cell rows. In front of the outlets, a small ampulla can be observed. The posterior two-thirds of the miracidium is filled with germinal tissues, situated in the germinal cavity /LENGY, 1960/. The cavity is covered with the subepithelium, containing the germinal cells bedded in a granular substance / figs . 4 and 12/. The borders of the cavity can be hardly defined, since the germinal tissue is a rather elastic mass, its dimensions depending on the movements of the miracidium. In fixed preparations, the tissue covers an area of 35x50 and joins the subepithelium at several points with fine and elastic fibres. The subepithelium and germinal tissue nuclei can easily be separated on the basis of their shape and chromophilous affinity. The nuclei of the former are oval, containing numerous chromatine grains, those of the latter are irregular in shape and their chromatine substances concentrated in one point in the middle of the nucleus / fig. 4 /. The embryo balls appear anterior to the germinal tissue, consisting of several cells /12-18/ in general, which are demarcated by a common thin membrane . Discussion During our investigations, the eggs were incubated in every ca-
