51-54. Spermatocytes in spireme stage, nucleus containing a nucleolus (n), and a chromatin element (x), which is attached to one end of spireme and gradually increases in size during growth stage of spermatocytes.
55. Spireme longitudinally split and showing the beginning of cross formation.
56. Spireme segmented, tetrads forming.
57. One split segment and a part of another connected by bands of linin.
58. More open cross and diamond forms; element x conspicuous.
59-60. More contracted cross and diamond-shaped tetrads; linin bands shown in 60, where element x is also present.
61. Different forms assumed by element x during tetrad stage (figs. 56-60).
62-63. Diamond-shaped and contracted cross-shaped tetrads from metaphase of first maturation mitosis, showing linin connections.
64. Diamond-shaped tetrad with spindle-fibers attached; a-a, probably halves of one univalent chromosome; b-b, halves of the other.
65. Dyad from anaphase of first maturation mitosis.