Electron and Light Microscopical Studies on Spermateliosis in a Boar With Acrosome Abnormalities

Summary. The development of the acrosome was studied in three normal boars and in one sterile boar with acrosome abnormalities. These abnormalities appeared mainly during three stages of spermiogenesis: (1) in spherical spermatids during the late cap phase, as an invagination of the interior membrane of the acrosomic cap with concomitant sinking of the acrosomic granule into the depression thus formed; (2) in elongated spermatids during the late acrosome phase, as an asymmetrical, extensive, curved process into the Sertoli cell cytoplasm; and (3) during the maturation phase by persistence of a tongue-like protrusion of the acrosome normally present only during the late acrosome phase. It is suggested that the common feature of the different types is an abnormal growth tendency in the acrosomic system.