482 Yasui. — On the Life-history of Salvinia natans. 
Fig. 52. Cross-section of an antheridium, showing an elongating blepharoplast in each sperm-cell, 
x 1400. 
Fig. 53. A mature male prothallium; the root-cell is not shown, x 1400. 
PLATE XL1I. 
Fig. 54. The initial-cell of a macrosporangium, x 600. 
Fig* 55* Three young macrosporangia in various stages of development, x 600. 
Fig. 56. A young macrosporangium in which the tapetum-initials are cut off. x 600. 
Fig. 57. A little later stage in which the central cell is divided once, x 600. 
Fig. 58. The second division of the central cell, x 600. 
Fig. 59. Eight macrospore-mother-cells are formed, x 600. 
Fig. 60. Cross-section of a macrosporangium, in which the macrospore-mother-cells are in the 
synapsis stage, x 600. 
Fig. 61. A macrospore-mother-cell whose nucleus is in the resting stage, x 1400. 
Fig. 62. Macrospore-mother-cell whose nucleus is in the synapsis stage, x 1400. 
Fig. 63. The same in early spireme stage, x 1400. 
Fig. 64. A later stage of the same, x 1400. 
Fig. 65. Three macrospore-mother-cells in which the chromosomes are just formed, x 1400. 
Fig. 66. A slightly later stage ; the diakinesis. x 1400. 
Fig. 67. The formation of the multipolar spindle, x 1400. 
Fig. 68. Cross-section of an equatorial plate, showing eight bivalent chromosomes, x 1400. 
Fig. 69. Spindle of the first division, x 1400. 
Fig. 70. The same as above, x 1400. 
Fig. 71. Telophase of the first division, x 1400. 
Fig. 72. The two daughter-nuclei of the first division, x 1400. 
Fig* 73- The prophase of the second division, x 1400. 
Fig. 74. The telophase of the second division, x 1400. 
Fig* 75* The granddaughter-nuclei are formed, x 1400. 
Fig. 76. Macrospore-tetrad, x 1400. 
Fig. 77. Young macrospores, x 1400. 
Fig. 78. A macrosporangium containing macrospore-tetrads, x 450. 
Fig. 79. A later stage with free macrospores, x 450. 
Fig. 80. The functional macrospore (m.) is located at the centre, and all the other potential 
macrospores are moving towards the periphery of the macrosporangium, x 450. 
Fig. 81. A later stage; the functional macrospore is surrounded by the cytoplasm and nuclei of 
disorganized tapetum-cells. x 260. 
Fig. 82. A still later stage, x 260. 
Fig. 83. Radial section of the spore-coat of a young macrospore, x 600. 
Fig. 84. Radial section of the spore-coat of an older macrospore; n, nucleus of the tapetal 
cell ; ep , epispore ; ex, exospore, x 260. 
Fig. 85. The tangential section of the same, x 260. 
Fig. 86. The first division of a germinating macrospore, x 800. 
Fig. 87. Upper part of a young female prothallium, x 800. 
Fig. 88. The initial-cell of an archegonium. x 800. 
PLATE XLIII. 
Fig. 89. A young archegonium ; a primary neck-cell is just formed, x 800. 
Figs. 90-92. The division of the central cell, x 800. 
Fig. 93. The division is completed and the neck canal-cell is formed above, x 800. 
Fig. 94. The ventral canal-cell is formed by the second division of the central cell, x 800. 
Fig. 95. The division of the nucleus of the neck canal-cell, x 800. 
Fig. 96. A mature archegonium. x 800. 
Fig* 97* An egg-cell just after the entrance of a spermatozoid. x 800. 
Fig. 98. An archegonium, showing numerous spermatozoids entering it; the egg is already 
fertilized, x 800. 
