19. —— ’89, 2: Beiträge zur Kenntniss der Zelle und ihrer Theilung, IV und V. Arch. f. mikr. Anat., Bd. 33. 20. Vom Rath, O., ’92: Zur Kenntniss der Spermatogenese von _Gryllotalpa vulgaris_. Arch. f. mikr. Anat., Bd. 42. 21. St. George, v. la Valette, ’67: Ueber die Genese der Samen Körper. Arch. f. mikr. Anat., Bd. 3. 22. —— ’86, 1: Spermatologische Beiträge, Zweite Mittheilung. Arch. f. mikr. Anat., Bd. 27. 23. —— ’86, 2: Spermatologische Beiträge, Vierte Mittheilung. Arch. f. mikr. Anat., Bd. 28. 24. —— ’87: Zelltheilung und Samenbildung bei _Forficula auricularia_. Festschrift f. A. v. Kölliker. 25. —— ’97: Zur Samen- und Eibildung beim Seidenspinner (_Bombyx mori_). Arch. f. mikr. Anat., Bd. 50. [B]26. Sutton, W. S., ’00: Spermatogonial Divisions in _Brachystola magna_. Kans. Univ. Quart., vol. 9. 27. Wilcox, E. V., ’95: Spermatogenesis of _Caloptenus femur-rubrum_ and _Cicada tibicen_. Bull. of Mus. of Comp. Zool. Harvard., vol. 27. 28. —— ’96: Further Studies on the Spermatogenesis of _Caloptenus femur-rubrum_. Bull. of Mus. of Comp. Zool. Harvard., vol. 29. [B] Nos. 12 and 26 were used when describing the material only and not the spermatid transformations. Explanation of Plate II. All drawings were made by the author with the aid of a camera lucida. All figures except 2, 3, 4 and 45 were made with a B. & L. 1/16 objective and one inch eye-piece, producing a magnification of 1340 diameters. Figs. 2, 3, 4 and 45 were drawn with a Leitz 1/16 objective and a Zeiss compensating ocular No. 12, giving a magnification of 2325 diameters. The drawings were not reduced in the photo-mechanical reproduction. FIG. 1. An early telophase, in which the fibers appear like barrel staves. Some of the fibers have thickened. FIG. 2. A later stage, in which the fibers are uniting, the clear space is forming, and the chromosomes are beginning to separate. FIG. 3. A daughter-cell, showing the chromosomes separating and the fibers thickening. FIG. 4. The chromosomes are scattered over the nuclear membrane; the fibers appear as a few thick rods. The beginning of the acrosome is seen. The accessory chromosome can be distinguished. FIG. 5. Same as fig. 4, with some of the fibers curved and no acrosome. FIG. 6. Same as fig. 5, but with the acrosome visible. FIG. 7. The chromosomes are granular; the fibers have bent and formed the round “striated nebenkern.” The acrosome is present. FIG. 8_a_. Same as fig. 7, but the acrosome is not present. FIG. 8_b_. The fibers run parallel with the long axis of the nebenkern. FIG. 9. Here is shown a partial end view of the nebenkern. The accessory chromosome and the acrosome are both prominent. FIG. 10. The nebenkern shows some of the fibers on the under side. It is beginning to break up. FIG. 11. The nebenkern shows the beginning of the dark center; the fibers extend from it to the ring. The acrosome has a peculiar appearance.