| ultrastructure of spermiogenesis and spermatozoa of neopolystoma spratti (platyhelminthes, monogenea, polystomatidae). | spermiogenesis in neopolystoma spratti conforms to the basic pattern found in polyopisthocotylean monogeneans and in trematoda digenea and trematoda aspidogastrea. the zone of differentiation exhibits a complete ring of cortical microtubules, two initially free flagella with prominent striated rootlets and an intercentriolar body between them. mitochondria and nucleus migrate into a median cytoplasmic process and flagella rotate and fuse with this process. mitochondria fuse to form a single elon ... | 1995 | 7624294 |