Microtubules in Spermatozoa of <i>Childia</i> (Turbellaria, Acoela) Revealed by Negative Staining

Abstract

Many intact axial units, with attached basal plates, are found in spermatozoa of Childia groenlandica negatively stained with phosphotungstic acid. Electron micrographs show a total of nine doublet microtubules, confirming observations on sectioned material, where nine peripheral doublets, but no single central ones, occurred. Living spermatozoa move by waves progressing along a double undulating membrane.