Scanning electron microscopy of the infective eggs of Hydatigera taeniaeformis.

Scanning electron microscopy of the outer surface coat of the infective eggs of Hydatigera taeniaeformis examined at high magnifications revealed the presence of scale-like features. At low magnifications the surface of eggs appeared smooth. Eggs that were fractured showed a thick inner surface layer of ridges and striations. A second layer characterized by a smooth membrane surface presumably the basement membrane was observed beneath the innermost surface layer. When the eggs were treated with 0.02 M of EDTA the outer surface coat became distorted and the emerging hooks of the embryo could be seen. Small, spherical bosses were observed on the surface of some eggs. Other eggs possibly at an earlier stage of development contained pit-like depressions.