FIG. 13. Metaphase of the first spermatocyte. The accessory chromosome is seen at one pole of the spindle, to which it has moved before the separation of the chromatids of the remaining chromosomes. FIG. 14. Another cell in about the same stage as that represented in the preceding figure. FIG. 15. A first spermatocyte metaphase in which the accessory chromosome has not as yet moved to the pole of the spindle. This is uncommon in _Orchesticus_, but frequent in _Anabrus_. FIG. 16. Pole view of a first spermatocyte metaphase, showing seventeen chromosomes. The variation in size of the elements, so marked in the spermatogonia, is even more pronounced here. This is a cell similar to that of figure 15, in which the accessory chromosome lies in the equatorial plate. [Illustration: Spermatocytes] Explanation of Plate VIII. FIG. 17. Two cells in metaphase—a pole view of one and an oblique view of the other. The accessory chromosome does not show in the former, the cell being such a one as is represented in figures 14 and 15. FIG. 18. Pole view of another cell, showing but sixteen chromosomes. FIG. 19. Early anaphase of the first spermatocyte, with the accessory chromosome already at one pole. FIG. 20. Mid-anaphase, with the giant chromosome still undivided. FIG. 21. Later anaphase, in which the accessory chromosome is seen at the lower pole. This figure shows, also, the character and extent of the intercellular material. FIG. 22. Later anaphase. The accessory chromosome at the upper pole. An undivided chromosome lying between the groups of daughter chromosomes. FIG. 23. About the stage of figure 22, but the lagging chromosome has divided. FIG. 24. Very late anaphase. Here, again, the lagging chromosome is divided. FIG. 25. Pole view of first spermatocyte telophase, showing the accessory chromosome at one side of the daughter chromosomes. FIG. 26. Pole view of a cell in the same stage as that represented in figure 25. Here, however, the accessory chromosome is not present. FIG. 27. Lateral view of telophase, with the accessory chromosome in the lower daughter-cell. FIG. 28. Fragment of second spermatocyte, showing the chromosomes in metaphase. The relative sizes of the accessory chromosome and the remaining chromosomes is well shown. FIG. 29. Metaphase of a second spermatocyte, in which the accessory chromosome is not present. FIG. 30. Anaphase of second spermatocyte, in which there is no accessory chromosome. FIG. 31. Anaphase of second spermatocyte, where the accessory chromosome is present—_x_^1 and _x_^2. FIG. 32. Telophase of the same class of second spermatocytes. The accessory chromosome extends out from the mass of chromosomes at each pole—_x_^1 and _x_^2. FIG. 33. Telophase of the class of second spermatocytes from which the accessory chromosome is absent. [Illustration: Spermatocytes] Explanation of Plate IX.