146 L. Digby, A critical study of the Cytology of Crepis virens. 
Fig. 96. The tetrads are about to separate. The chromatic contents of the nu- 
clei are visible as rounded beads. 
Fig. 97. Tetrad nucleus. As the tetrad nuclei pass into rest the chromatic beads 
fragment. 
Fig. 98. The beads gradually conceutrate to form larger aggregations. One 
such aggregation is seen in this nucleus. 
Fig. 99. Shows the diminution in number of the clmomatic beads as they gra- 
dually amalgamate. 
Fig. 100. Resting tetrad nucleus with two definite chromatic bodies, one of 
which is composed of two rounded chromatic beads. Linin Strands with other faintly 
staining beads traverse the nucleus. 
Fig. 101. Resting tetrad nucleus with two chromatic bodies. The linin with its 
faintly staining granules shows a paired arrangement. 
Fig. 102. Alternative series of presynaptic phases. Early prophase showing 
the linin reticulum and a fine distribution of chromatin in its meshes. In parts the 
chromatic contents are concentrated into larger masses. This series Figs. 102 — 110 
has beeil fixed with Merkel and has been taken from the same slides as Figs. 40 — 62. 
Fig. 103. Later stage in which the chromatin is more widely distributed as small 
beads throughout the linin. 
Fig. 104. The beads begin to collect together, and the pairing of beaded threads 
is to be seen. 
Fig. 105. Further concentration of the chromatin especially at the periphery 
of the nucleus. 
Figs. 106 and 107. The concentration of the chromatin, and the approximation 
of paired strands, results in the formation of thickened beaded portions, and dense 
amalgamations of chromatin. 
Figs. 108 and 109. Show stages in the withdrawal of the reticulum with the 
various sized chromatic beads preparatory to synapsis. 
Fig. 110. The nuclear contents are becoming closely massed prior to complete 
synapsis. 
Fig. 111. Resting nucleus between the last archesporial division and the hetero- 
type prophase showing definite chromatic bodies. This series of presimaptic phases 
Figs. 111 — 117 has been taken from a slide fixed with acetic alcohol. 
Fig. 112. Resting nucleus with chromatic aggregations. 
Fig. 113. Early heterotype prophase. The chromatic bodies are beginning to 
Show signs of fission. 
Fig. 114. Each split side of a chromatic body rounds itself off as a bead; a 
chromatic body therefore is often represented by a pair of beads. 
Figs. 115 and 116. The beads begin to conceutrate, and to collect in groups 
prior to synapsis. 
Fig. 117. A superficial section of a nucleus whose contents are massing together 
preparatory for synapsis. The chromatic substance diffuses throughout the linin, leaving 
110 aggregations of chromatiii. 
Fig. 118. Tapetimi. Resting nucleus with one chromatic body. 
Fig. 119. Resting tapetal nucleus with two chromatic bodies. 
Fig. 120. Resting tapetal nucleus with three chromatic bodies. 
