Yasui. — On the Life-history of Salvinia natans . 483 
Fig. 99. The upper part of a germinating macrospore, showing young prothallium with an 
archegonium. x ioo. 
Fig. 100. Longitudinal section of a prothallium, with five archegonia. x ioo. 
Fig. 101. A fertilized egg-cell, preparing for the first division, x 600. 
Fig. 102. Two-cell stage of the embryo, x 600. 
Fig. 103. One of the two cells is dividing, x 600. 
Fig. 104. The stem and cotyledonary quadrant-cells are dividing, x 600. 
Fig. 105. The four-cell stage, x 600. 
Fig. 106. The upper two cells are divided by cross- walls, x 600. 
Fig. 107. An apical cell is formed in each stem and cotyledon quadrant, x 600. 
Fig. 108. A later stage, x 600. 
Fig. 109. A still later stage, x 600. 
Fig. no. Longitudinal section of a young plant, x 360. 
Fig. hi. Longitudinal section of the cotyledon, x 360. 
Fig. 1 1 2. Two embryos in the same prothalium. x 600. 
Fig. 1 13. A cell of a young sporophyte. x 1400. 
Figs. 114-119. Various stages of the division of the cells of a young sporophyte. x 1400. 
