a1 Zoology Department, University of Oklahoma, 730 Van Vleet Oval, Norman, Oklahoma 73019, USA
a2 School of Biological Sciences, The Queen's University of Belfast, Belfast, Northern Ireland, UK
a3 Zoology Department, Aligarh Muslim University, Aligarh 202 001, India
The morphology of the tegument in the redia of Paramphistomum epiclitum (Digenea: Paramphistomidae) resembles that shown by most larval and adult digeneans; an outer surface syncytium is in continuity with the cytoplasm of in-sunken, nucleated cytons. Although tegumental cytons usually contain a single nucleus, some display up to six nuclei. The tegumental syncytium lining the pharynx of P. epiclitum rediae lack underlying cytons. The apical membrane of the tegument is elaborated by folds and microvilli, which presumably facilitate uptake of nutrients and/or exchange of ions involved in osmoregulation. A single type of secretory body, resulting from the fusion of smaller vesicles produced at Golgi complexes in the cytons, occurs throughout the tegument. Uniciliate sensory receptors occur in the surface syncytium particularly around the oral opening.
(Accepted April 15 1992)
c1 T. S. Dunn, Dept. Pathology, BMSB Rm 434, P. O. Box 26901, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190, USA.