3OO ELIZABETH A. SMITH. 



PLATE V. 



Libellula basalis. 



FIG. 80. Spermatogonium from aceto-carmine preparation. 



FIG. 81. Spermatogonium from iron-hematoxylin section. 



FIG. 82. Spermatogonium from fresh material (X 1,500). 



FIG. 83. Prophase chromosomes of Spermatogonium. 



FIGS. 84 AND 85. Polar view of chromosomes of last spermatogonial division. 



FIGS. 86-90. Spermatogonial division stages. 



FIG. 91. Formation of leptotene threads. 



FIGS. 92, 93 AND 94. Spireme stages from aceto-carmine preparations. 



FIG. 95. Spireme stage from fresh material. 



FIGS. 96, 97, 98 AND 99. Polar views of chromosomes of primary spermato- 

 cyte division. Fig. 97 is from an aceto-carmine preparation and shows only 12 

 chromosomes. Figs. 98 and 99 are taken from the same cell, at different focal 

 levels. 



FIGS. 100, 101, 102 AND 103. Various stages in primary spermatocyte division 

 showing the sex-chromosome going to one pole undivided. 



FIG. 104. Metaphase of primary spermatocyte division from an aceto-carmine 

 preparation. 



FIGS. 105 AND 106. Primary spermatocyte stages (X 1,500) from fresh 

 material. 



