ULTRASTRUCTURE OF SPERMIOGENESIS AND SPERMATOZOA IN THE MONOGENEANS CONCINNOCOTYLA-AUSTRALENSIS (POLYSTOMATIDAE) AND PRICEA-MULTEE (GASTROCOTYLIDAE)

Spermiogenesis in Concinnocotyla australensis and Pricea multae involv es the formation of a zone of differentiation containing cortical micr otubules, on intercentriolar body flanked by two basal bodies, and cil iary rootlets; a median cytoplasmic process grows between the two flag ella which bend to lie parallel and fuse with the process in a proxima l to distal direction. In both species an additional structure, a ''sp ur'', not previously documented in parasitic platyhelminths, is connec ted to the base of each basal body during spermiogenesis. Mature sperm of both species are Filiform with two fully incorporated axonemes thr oughout most of the sperm body, a single elongate mitochondrion, a cor tical ring of microtubules for much of their length, and an incomplete ring of fewer microtubules, with attachment zones present in the dist al regions. The nucleus in P. multae sperm is wedge-shaped in cross se ction in the principal region, while that of C. australensis partially or completely enwraps the mitochondrion and two axonemes for much of its length C. australensis sperm has a proximal bilateral flange lined with additional microtubules and surrounded by extracellular material . P. multae has a smell, one-sided, microtubule-lined flange.