24 Miyake, The develop:nent of the gametophytes etc. 



Fig. 70. A same stage as above, showing a pollen-tube just reached the 

 archegonia. X 50. 



Fig. 71. Outline ol longitudinal section of a similar prothallium as the 

 preceding; position of sterile prothallial tissue is shown. 50. 



Fig. 72. Cross-section of upper part of mature prothallium; sterile pro- 

 thallial tissue in the center of archegonial complex is shown. < 90. 



Fig. 73—75. Abnormal neck-cells. < 270. 



Fig. 76. A neck seen from above. ,< 270. 



Fig. 77. Central cell of archegonium in division. X 160. 



Figs. 78 — 81. Successive stages in division of central cells of arche- 

 gonium. X 660. 



Fig. 82. Young egg with remnants of ventral canal-nucleus above. 

 X 160. 



Plate IV. 



Fig. 83. Young egg. X 160. 



Figs. 84^86. Mature or nearly mature eggs. ;< 160. 



Fig. 87. Longitudinal section of upper part of mature prothallium, 

 showing mature eggs and sperm-cells ready for fertilization. ,< 50. 



Fig. 88. Two sexual nuclei little before conjugation. ,< 270. 



Fig. 89. Sexual nuclei in fusion. X 270. 



Fig. 90. The same. ;< 660. 



Fig. 91. Beginning of first spindle-formation after fertilization. ,< 660. 



Fig. 92. Spindle fuUy established. X 660. 

 . Fig. 93. Telophase of first division; an extra karyokinetic figure at the 

 upper part of egg. X 330. 



Fig. 94. Two daughter-nuclei of first division. >C 660. 



Fig. 95. The same at the base of archegonium; an extra nucleus near 

 the tip. X 160. 



Fig. 96. The same stage as above. X 160. 



Fig. 97. Four free nuclei at the base of archegonium; only three of 

 them are shown. , 160. 



Fig. 98. Eight free nuclei at the base of archegonium; five of them are 

 shown. X 160. 



Fig. 99. A slightly later stage. Walls are formed between the nuclei 

 and nnclei of upper tier are dividing. < 160. 



Fig. 100. Division of upper tier of eight-celled proembryo. X 660. 



Figs. 100 — 102. Proembryo after division of nuclei of upper tier. X 160. 



Fig. 103. A little later stage; suspensors somewhat elongated. ~ 160 



Fig. 104. A still later stage, with longer suspensoi-s. X 160. 



Fig. 105. Abnormal female prothallium in which two archegonial complex 

 are present. X 50. 



Plate V. 



Fig. 106 a. Mature body-cell. 



Fig. 106 b. Another section of the same, showing two free nuclei below 



Fig. 107. Two sperm-cells. 



Fig. 108. Longitudinal section of a young ovule, showing young female 

 prothallium surrounded by several layers of tapetum cells. Several pollen-tubes 

 are seen at the tip of nucellus. 



