Plate IV. 



Second, Third aiid Fourth Cleavages of C. plana. 



Fig. 02. — Similar to preceding ; nucleus in early prophase. 



Fig. 63. — Section at right angles to preceding ; amphiaster for second cleavage present. 



Fig. 64. — Prophase of second cleavage. (Omitted from plate for lack of space and put in 

 text as tig. XVIII.) 



Fig. 65. — Metaphase of second cleavage. 



F"ig. 66. — Anaphase of second cleavage; chromosomes at the borders of the spheres; 

 latter alveolar. 



Fig. 67. — Anaphase of second cleavage; chromosomal vesicles apparently absorbing sub- 

 stance from spheres. 



Fig. 6S. — Telophase of second cleavage (horizontal section) ; centrosomes faintly granular. 



Fig. 69. — Rest stage at close of second cleavage ; centrosomes densely chromatic. 



Fig. 70. — Amphiasters for third cleavage moving out of spheres and old centrosomes; 

 nuclei show polar differentiation of the chromatin. 



Fig. 71. — Prophase of third cleavage ; nuclei indented ; sphere remnants at apical pole. 



Fig. 72. — Metaphase of third cleavage. 



Fig. 73. — Telophase of third cleavage. 



Fig. 74. — Resting stage after third cleavage. Centrosomes are reticular spindles. 



Fig. 75. — Same stage as preceding ; section through one macromore showing the centro- 

 some, which becomes the amphiaster of the fourth cleavage, a.s a reticular spindle. 



Fig. 76. — Subdivision of the first quartette ; spindle in metaphase in one cell ; amphiaster 

 just escaped from the sphere in the other ; nucleus and spheres of the second quartette cells shown. 



