| Comprehensive ultrastructural investigation of spermiogenesis and the mature sperm in <i>Thylacorhynchus ambronensis</i> revealed a number of features valuable for cladistic analysis. Two basal bodies lie on either side of an intercentriolar body in the zone of differentiation of the spermatid, but only one develops into a normal flagellum while the other remains as a small bud, eventually disappearing. Structures within and surrounding the two basal bodies differ, and, contrary to observations in another monoaxonemal schizorhynch (<i>Baltoplana magna</i>), the two basal bodies become separated and only that of the normal flagellum is carried distally from the cytophore which unites an isogenic group of spermatids. A spiralling... |
