[Ultrastructural similarity of spermatozoa of some Cyclophyllidea]

The mature spermatozoa of Cotugnia polyacantha, Raillietina (R) tunetensis, Inermicapsifer madagascariensis and Avitellina centripunctata have an almost identical ultrastructural organization. They are tapered at both extremities. Their anterior extremity exhibits an apical cone of electron dense material and one or two helicoidal crested-like bodies. Their cortical microtubules are spiralized and are seen, in longitudinal and cross sections, as continuous, dense, submembranous material. Their nucleus is a cord of dense chromatin, coiled in a spiral around the 9 + "1" pattern axoneme. The cytoplasm is moderately dense to electron lucent and exhibits irregularly spaced walls of proteinaceous material and a fine periaxonemal sheath of dense material. In this work we show that the Anoplocephalidae are close to the Davaineidae by the characters of the spermatozoon and that Inermicapsifer should be put back among the Davaineidae, according to the opinion of Joyeux & Baer (1961) and come into conflict with other works more particularly Schmidt (1986).