Scanning electron microscope observations on the miracidium of Schistosoma

Miracidia of two species of Schistosoma, viz. haematobium and japonicum, were studied with the scanning electron microscope to more clearly visualize what is seen with the light microscope and the transmission electron microscope, and more specifically, to relate the structure of the apical papilla to its function in snail penetration. The apical papilla of schistosome miracidia is composed of corrugated areas which form tiny suckerlike cups, presumably used by the miracidium to facilitate attachment to the snail during penetration. A lateral opening (secretory pore) on the apical papilla and short stubby apical cilia (tactile or sensory) are also demonstrated.