A Note on the Development of the Metacercarial Cyst of Holostephanus lühei Szidat, 1936

Abstract

Cercaria spatulata is synonymized with Holostephanus lühei on the basis of the close morphological similarity between naturally occurring cysts of H. lühei and those experimentally reared from C. spatidata in Pygosteus pungitius. Observations on metacercariae from one day to ten weeks old showed that development of the cyst is completed within six weeks. The completed cyst is wider and its internal diameter smaller than young stages, which suggests that the metacercaria shrinks during development and that the cyst expands inwards to occupy the space left. The cyst is deposited within two to three weeks and increases in width as the metacercaria contracts during development.