Embryos and embryonic envelopes in eggs of two cyclophyllidean cestodes

Membranes and envelopes around the embryos in eggs of Cotugnia digonopora and Raillietina (R.) echinobothrida have been studied in detail. This is the first study giving details of the egg-shell of a Cotugnia species. There are 3 membranes and an equal number of envelopes around the embryos in eggs of C. digonopora , while there are 2 membranes and only one envelope in case of eggs of R. echinobothrida . Noteworthy is the presence of a membrane in eggs of C. digonopora , termed "middle capsule", between and separating the 2 envelopes viz. the outer and inner. The membranes and envelope around the embryos in eggs of R. echinobothrida have been found to be identical with those of R. galeritae .--The 3 pairs of embryonic hooks of the 2 cyclophyllideans studied are collared --a feature of specific importance.