Ultrastructure of the flagellum in sperms of the scorpion Tityus bahiensis

In spermatids of the scorpion Tityus bahiensis two centrioles appear coaxially aligned. The flagellum shows 9 peripheral doublets and a central rod (9 + 1 pattern). This central rod, of about 15 nm in diameter, is positively stained when a cytochemical method for histone staining is used. Longitudinal sections show that radial spokes are apparently in groups of three and showing a basic repeat of about 94 nm.