PLATE 21 



Fig. 67. Early stage of chromatin extrusion. Enlarged nucleus, small karyo- 

 some in the center with light area, then a dark peripheral region around it. 



Fig. 68. Later stage. The chromatin around the expurged karyosome has 

 fused to form larger granules. Stainable lines extend outward to the nuclear 

 membrane. 



Fig. 69. The two masses at opposite sides of the nucleus. Connecting fibers 

 broken. 



Fig. 70. Karyosome moving out of the chromatic globe. 



Fig. 71. The karyosome has broken through the chromatic globe. 



Fig. 72. Section showing the relation of the karyosome to its peripheral cup 

 immediately prior to its emergence. 



Fig. 73. The two masses are nearly separated. 



Fig. 74. The two masses are at opposite sides of the nucleus. 



Fig. 75. The peripheral chromatin is spread out on the nuclear membrane, 

 the karyosome is at the center. Chromidia are found in the cytoplasm. The 

 cyst wall is being formed. 



Fig. 76. The peripheral chromatin is cup-shaped and the karyosome is 

 emerging. 



Fig. 77. Binucleate individual with peripheral chromatin on the nuclear 

 membrane at the adjacent sides. 



Fig. 78. Peripheral chromatin nearly gone. Chromidia are numerous. 



Fig. 79. Outer cyst wall formed. Few chromidia, and no pores. 



Fig. 80. Amoeba with nuclei, in the same stage as that of figure 76. 



Fig. 81. Cyst wall completed. Pores do not show in the position drawn. 

 No peripheral chromatin is remaining. The chromidia are very numerous and 

 they are irregular in shape as they are in the other figures. The cytoplasm is 

 dark near the nucleus. 



Fig. 82. An amoeba preparing to encyst. The vacuole is very large. There 

 are no food vacuoles. 



Fig. 83. Both walls are formed. One pore is shown. 



Fig. 84. Cyst with two nuclei in which the karyosomes are broken up and 

 one large mass of extranuclear chromatin. 



Fig. 85. Old cyst with one mass of chromatin in the cytoplasm and broken 

 up spindle-like karyosome. 



Fig. 86. Another appearance presented by the karyosome of an old cyst. 



Fig. 87. Cyst with three nuclei. 



Fig. 88. An amoeba trying two exits. Vacuoles numerous. 



Fig. 89. An amoeba emerging. 



Fig. 90. An amoeba trying to emerge at two pores. 



1288] 



