|Comparative fine structure and origin of the metacercarial cyst in two philophthalmid trematodes, Parorchis acanthus (Nicoll, 1906) and Philophthalmus megalurus (Cort, 1914)|
Cable, R.M.; Schutte, M.H. (1973). Comparative fine structure and origin of the metacercarial cyst in two philophthalmid trematodes, Parorchis acanthus (Nicoll, 1906) and Philophthalmus megalurus (Cort, 1914). J. Parasitol. 59(6): 1031-1040
In: The Journal of Parasitology. American Society of Parasitologists: Lawrence, Kan., etc.,. ISSN 0022-3395, more
Parorchis acanthus (Nicoll, 906) Nicoll, 1907 [WoRMS]; Philophthalmus megalurus (Cort, 1914); Marine
|Authors|| || Top |
- Cable, R.M.
- Schutte, M.H.
In Parorchis, the cyst wall has 3 layers with the innermost laminated and formed by secretions of batonnet glands as in Fasciola. The cyst of Philophthalmus has only the other 2 layers; batonnet cells are lacking and not replaced by another gland type. In Parorchis, all 3 layers are well defined but only the outer one is in Philophthalmus. In both, the tegument of emerging cercariae is thickened with inclusions released to form the outer cyst layer and indicated by their variety and location in the tegument to be secretions of divers glands in the parenchyma of developing larvae. Additional types in the parenchyma of emerging cercariae are depleted during encystment but their role in that process is obscure as is the source of the inner (middle in Parorchis) layer. In Philophthalmus at least, its source must be in the parenchyma to account for the extent to which the worm shrinks as it encysts. A ventral plug in Parorchis cysts was not evident and the cyst neck in Philophthalmus is closed at the end by a weak wall ruptured during excystment.