Abstract
When animals were irradiated early in spermiogenesis, i.e., at the spherical nucleus stage, 2 or more flagella were formed in many cells at the subsequent stages. Other irradiation effects included the absence of cytoplasmic microtubules at an early stage followed by their excessive production later during formation of the flagellum, the abnormalities in structure of the mitochondrial sheath around the axoneme and the extremely disordered arrangement of flagellar components. The basal body and axoneme showed a normal structure at all stages, and acrosome development appeared to be unaffected by the irradiation.