The Development of Organ Systems in Nematotaeniid Cestodes. I. Early Histogenesis and Formation of Reproductive Structures in Baerietta diana (Helfer, 1948)

Most accounts of histogenesis in adult cestodes appeared in the literature before 1935. These include the studies of Young (1908-1935) in Taenia serrata and Child (1907 and 1911) on Moniezia benedeni and M. expansa, Johnstone (1911) on Tetrarhynchus erinaceus, Vogel (1929 and 1930) on Dibothriocephalus latus, Wisniewski (1930) on the genus Archigetes, and Michajlow (1932) on Triaenophorus nodulosus. One thorough account (Balss, 1908) was limited to the formation of sex ducts in Anoplocephala magna and A. perfoliata. In none of these works, however, has an attempt been made to determine the cellular origin of each tissue component in mature and gravid proglottids. In particular, morphogenetic movements have not been analyzed. In the present series of papers, an attempt is made to identify primitive cell types near the anterior end of the adult strobila and to trace