Spermatozoon of Prosotocus confusus, posterior or nuclear part (Region III); all cross-sections. (a, b) Disappearance of cortical microtubules (CM); G, granules of glycogen; M2, second mitochondrion; N, nucleus. (c) Level of disorganization of the first axoneme; CC, central core; M2, second mitochondrion; N, nucleus. (d–f) Consecutive sections showing the disappearance of the second mitochondrion (M2) and the progressive reduction of the size of nucleus (N). G, granules of glycogen. (g, h) Level of the posterior spermatozoon tip. G, granules of glycogen. Scales in μm: 0.3.