The spermatogenesis of Peripatus (Perîpatopsis) balfouri. 361 



Figs. 53 — 55. Spermatogonic dyasters, pole views of the daughter 

 plates of chromosomes. 



Fig. 56. Early anaphases of spermatogonia, nuclear membrane 

 still absent ; D a cell in pole view, A — C cells in slightly oblique 

 lateral views. 



Fig. 57. Spermatogonium metaphase; chromosomes so closely 

 compacted that their outlines are indistinguishable. 



Fig. 58. Spermatogonium, early anaphase; in only one daughter 

 cell (1st spermatocyte) are structural details shown. 



Fig, 59. Spermatogonic dyaster, about stage of preceding figure, 

 pole view. 



Figs. 60, 61. Spermatogonic dyaster, lateral view; first appearance 

 of longitudinal split in chromosomes, and in the lower cell of Fig. 60 

 first appearance of nuclear membrane. 



Fig. 62 Spermatogonic dyasters, about stage of Fig. 57 ; chromo- 

 somes closely compacted ; cytoplasmic constriction not completed the 

 obliquity of view causing the daughter cells to appear separated. 



Fig. 63. Lateral view of early spermatogonic anaphase, only a 

 few of the chromosomes of each daughter cell shown. 



Plate 20. 



Fig. 64. Early synapsis, lateral view. 



Fig. 65. Two 1st spermatocytes, still connected by the Zwischen- 

 körper, early synapsis ; only a few of the chromosomes shown. 



Figs. GG, 67. Lateral views of synapsis stages, cytoplasmic details 

 hot shown. In these figures, as in all following representing lateral 

 views of spermatocytes from the synapsis up to the monaster of the 

 1st maturation division, the central pole of the cell is directed towards 

 the top of the Plate, the distal pole towards the bottom. 



Fig. 68. 1st spermatocyte, synapsis (?) stage, with unusually well- 

 marked longitudinal split of the chromosomes. 



Fig. 69. Oblique section of two spermatocytes in synapsis stage, 

 all chromosomes not shown. 



Figs. 70 — 72, Lateral views of synapsis stages. 



Fig. 73. Lateral view of synapsis stage, showing two entire 

 chromosomes. 



Figs. 74, 75. Lateral views of synapsis stages, in each figure one 

 cell simply outlined. 



Figs. 76 — 78. Lateral views of synapsis stages, only a few of the 

 chromosomes shown; only in Fig. 77 cytoplasmic details, and there 

 also the earliest stage of the idiozome sphere. 



Fig. 79. Lateral view of nucleus in synapsis stage, showing 2 

 complete bivalent chromosomes. 



Figs. 80 — 82. Lateral views of synapsis stages, in all only a few 

 whole bivalent chromosomes drawn. 



Fig. 83. Lateral view of nucleus in synapsis stage. 



