Sporangia and Spores of Aneimia phyilitidis . 1065 
wall-cells filled with reserve food in those sporangia of Lygodium whose 
sporogenous cells have failed to produce spores. This is true of Aneimia 
also, but not of their sterile sporangia alone. I find, rather, that there is on 
the whole less starch in the sterile than in the fertile sporangia. 
The fact that there is such an abundance of stored food in the sporangia 
in all stages of their development, and that sterile sporangia contain reserve 
starch, suggests that sterilization may not be due to insufficient nutriment 
alone. 
Summary. 
1. Starting from one, or possibly more than one protoderm cell, a few 
initials of the sporangium wall are soon formed surrounding a central ceil, 
which proves to be the initial of the archesporium and tapetum. 
2. This initial by periclinal walls cuts off a layer of tapetal cells, each 
of which in its turn undergoes one periclinal division, and forms a two-layered 
tapetum. The single cell surrounded by these is the archesporium. 
3. The archesporium gives rise to approximately sixty-five gonotokonts 
or grandmother-cells of the spores. 
4. Before the archesporial divisions are complete the outer tapetal 
layer begins to break down, and this is soon followed by the similar behaviour 
of the inner layer, and the mass of gonotokonts thus becomes suspended in 
the common tapetal cytoplasm now forming a plasmodium. 
5. There is evidence that circulation of the tapetal cytoplasm takes 
place, which probably assists in the distribution of nutrient materials. 
6 . The sporangium increases in size up to the time of synapsis in the 
gonotokonts; then apparently growth is retarded during the progress of 
the meiotic divisions. 
7. The mature gonotokonts separate from each other, and the tapetal 
plasmodium flows in and entirely surrounds each one. 
8. From the time of synapsis to the completion of the meiotic divisions 
seems to be a critical nutritive period, for then it not infrequently happens 
that sporangia cease their growth and begin to disintegrate. 
9. No wall is seen around a gonotokont as it lies separately embedded 
in the plasmodium, and when the last meiotic division is finished the plasma 
membrane of the gonotokont persists as the external membrane of the 
tetrad. 
10. The separation of the young spores of a tetrad from each other is 
initiated by their expelling water and shrinking apart, and thereupon the 
tapetal plasmodium flows in between them. 
11. At a very early stage in its thickening the spore coat reacts as cutin 
does to the triple stain. Down the three angles of a spore this coat shows 
lines of fission. Very often in the preparations the exospore breaks apart 
down these lines into three distinct flaps. 
