20. A fragment of the seminal vesicle of Lecithochirium musculus containing spermatozoa. Scale bar = 2 μm. Spz = spermatozoon, V = seminal vesicle, Vw = seminal vesicle wall.

21–24. Region I of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (21). A longitudinal section of the anterior extremity of the spermatozoon showing the external ornamentation of the plasma membrane. (22). Cross-section in the anterior extremity of the spermatozoon showing the anterior extremity of the first axoneme and the external ornamentation of the plasma membrane. (23). Cross-section exhibiting the axoneme 1, the external ornamentation of the plasma membrane and singlets of the second axoneme. (24). Cross-section showing the two axonemes and the external ornamentation of the plasma membrane. Aae1 = anterior extremity of the first axoneme, Ase = anterior spermatozoon extremity, Ax1 = first axoneme, Ax2 = second axoneme, B = bulge, Eo = external ornamentation of the plasma membrane, S = singlet.

25–30. Cross-sections of Region II of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (25–26). Two axonemes and some cortical microtubules. (27–28). Two axonemes, cortical microtubules and the nucleus. (29). Two axonemes, cortical microtubules, the nucleus and the mitochondrion. (30). One axoneme, nucleus, mitochondrion, cortical microtubules and the posterior axonemal extremity 1. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus, Pae1 = posterior extremity of the first axoneme.

31–32. Cross-section of Region III of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (31). The second axoneme, nucleus, mitochondrion and some cortical microtubules. (32). The second axoneme, nucleus and some microtubules. Ax2 = second axoneme, Cm = cortical microtubules, Mt = mitochondrion, N = nucleus.

33–36. Cross-section of Region IV of the spermatozoon of Lecithochirium musculus. Scale bars = 0.2 μm. (33). Cross-section of the spermatozoon showing the second axoneme, nucleus and one cortical microtubule. (34). Cross-section of the spermatozoon showing the second axoneme disorganized and the nucleus. (35). Cross-section of the spermatozoon showing the nucleus surrounded by doublets from the second axoneme. (36). Cross-section showing the posterior extremity of the spermatozoon with only the posterior extremity of the second axoneme. Cm = cortical microtubules, N = nucleus, Pae 2 = posterior extremity of the second axoneme.

37. Transmission electron micrograph of spermatozoa of Lecithochirium musculus showing glycogen granules (G) revealed by the test of Thiéry. Scale bar = 0.2 μm.