The mature spermatozoon of Stilesia globipunctata Rivolta 1874 is tapered at both ends. The anterior extremity exhibits terminal dense material through which a single helicoidal crested-like body runs along the whole length. The axoneme is of the 9 + '1' pattern as in the other platyhelminthes, It is surrounded by radial rods of dense material, perpendicular to the surface of the axoneme and forming a pseudo-crystalline sheath made up of regular discs superposed from one extremity to the other of the axoneme. The cortical microtubules are wound in a spiral and opposed to the internal surface of the smooth plasma membrane. The nucleus, which is elongated and filiform, is wrapped in a spiral round the layer of radial rods and in close contact with the cytoplasmic membrane, separating the microtubules. The presence of a sheath of pseudo-crystalline material round the axoneme and the peripheral position of the nucleus separating the microtubules had never been observed before in a Cestode. Likewise, the presence of a single crested-like body as in the other Cestodes had never been reported in a Cyclophyllidea.
