Studies of an acrosomal defect in spermatozoa from a platinum fox

An acrosomal defect in the spermatozoa from a platinum fox was studied under light- and electron microscopy. The defect, occurring in about 40 % of the sperm cells appeared under phase-contrast and bright-field microscopy as a knob-like irregularity, mostly rounded or slightly triangular in outline and situated in the apical part of the sperm head. Electron microscopy of the sperm head revealed a marked deviation from the normal development of the acrosome. In most of the cases this structure contained a large membrane bounded vacuole filled with numerous small vesicles and some membranous material. In spermatids studied in the cap-phase, the developing acrosome exhibited a high degree of abnormal morphology, indicating that the development of the defect must have started rather early during the formation of the acrosome.