EN
The present paper compares the ultrastructural data on spermatology of three dipylidiid species (Dipylidium caninum, Joyeuxiella echinorhynchoides and J. pasqualei) and establishes a general pattern of spermiogenesis and main ultrastructural characters of the mature spermatozoa for the Dipylidiidae. Spermiogenesis is characterized by an external growth of the flagellum followed by a proximodistal fusion of the latter with the cytoplasmic extension. The centrioles are associated with striated rootlets which are thin in D. caninum and well-developed in Joyeuxiella spp. The most characteristic features of the mature spermatozoa of the three species are the presence of a single crest-like body and a periaxonemal sheath. Nevertheless, the three compared species differ in the thickness of these structures. Differences are also observed in the length of the apical cone.