Chemical nature and mode of stabilization of eggshell/capsule of some cyclophyllidean cestodes

The chemical nature and mode of stabilization of the eggshell/capsule of Moniezia expansa, Avitellina lahorea and Stilesia globipunctata have been investigated using histochemical techniques. In M. expansa where vitelline glands are present, the eggshell is stabilized by -S-S and -S-H linkages whereas in A. lahorea and S. globipunctata, the vitelline glands are absent and the double membranes, fibrous capsule and paruterine organ contain mainly elastokeratin-type structural protein. The possible role of the vitellaria in the presence or absence of eggshell and its thickness is discussed.