PLATE 14 



Nuclear changes in binary fission in Collodictyon. Any differences between 

 these figures and those of associated plates must be referred to the original 

 camera lucida sketches for critical interpretation. 



Figs. 65-76. Prophase phenomena. 



Figs. 63-65. Stages of the resting nucleus. 



Figs. 77-79. Metaphase. 



Figs. 80-83. Anaphase. 



Figs. 84-87. Telophase. 



Figs. 66-67. Unequal constriction of primary karyosome. 



Fig. 68-69. Differential division of the primary karyosome into a macro- 

 karyosome and a microkaryosome. Organization of a kinetic membrane around 

 the microkaryosome. 



Figs. 69-73. The segmenting skein, with associated expansion of the kinetic 

 membrane. 



Fig. 71. Precocious spindle formation. Macrokaryosome in a niche of the 

 nuclear membrane. 



Fig. 72. Double crescent stage of segmenting skein showing four terminal 

 knobs and a possible intranuclear division center dividing. 



Fig. 73. Longitudinal splitting of crescents, producing seven or eight termi- 

 nal knobs of chromatin which are the elements of the chromosomes. 



Fig. 74. Precocious spliting of peripheral chromatin granules. Precocious 

 equatorial plate formation with macrokaryosome upon it. 



Fig. 75. Final prophase. Division of blepharoplasts with apparent splitting 

 of flagella; separating centrosomes upon the nuclear membrane connected by a 

 paradesmose. 



Fig. 76. Precocious splitting of final stage of segmenting skein. Sixteen 

 chromatin masses in a chromatin cloud in the form of an equatorial belt. 



Fig. 77. Metaphase spindle. Macrokaryosome apparently a part of it. 

 Intranuclear chromatin cloud. 



Fig. 78. Metaphase spindle; centrosomes at poles of spindle and connected 

 by paradesmose. 



Fig. 79. Metaphase spindle showing seven chromosomes. Transverse parting 

 of all chromosomes except one which is only half so large as the rest. 



Fig. 80. Anaphase. Apparent unequal distribution of chromatin. 



Fig. 81. Anaphase. Daughter chromatin masses organized into linear 

 spiremes. 



Fig. 82. Anaphase. Linear spireme of chromatin granules closely related 

 to centrosomes, which are connected by paradesmose. 



Fig. 83. Telophase. Complete separation of daughter nuclei. Extranuclear 

 and intranuclear chromidial cloud. 



Fig. 85. Distribution of chromatin as granules throughout nucleus. 



Fig. 86. Eeorganization of central karyosome with surrounding hyaline area, 

 and peripheral chromatin. 



Fig. 87. Suspended telophase. Vesicular nucleus with small chromatin mass 

 of unknown significance near the periphery. Daughter blepharoplasts with 

 double basal granules surrounded by granular archoplasm. 



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