336 The Botanical Gazette. [June, 
somewhat enlarged sporogenous cell or cells begin to weaken 
and disorganize (fig. 4, @), and each sporogenous cell divides 
twice to produce four macrospores (fig. 5, f). The first di- 
vision is transverse and the second, which follows before the 
first wall develops to any thickness, is transverse in the lower 
cell and either transverse, oblique, or longitudinal in the 
upper cell. 
The female prothallium. 
A number of spores begin at once to develop female pro- 
thallia. They increase in length and grow toward the chalaza 
at the expense of the cells which lie in their paths, and the 
growing end of each becomes gradually larger. After about 
three weeks, April 8th, sacs are found with two nuclei (fg. 
8, 4). Already one sac is considerably larger than the oth- 
fourths becomes thicker. Usually the smaller sacs are a 
quarter of the sporangium W i“ 
they become tangled and surround the upper part of = fs 
cipal sac. This upper part of the principal sac becomes the 
phied and does not develop tissue. The formation * es 
cellular prothallium in the sac was not observed but It oe 
place about the first of June. When this occurs all or sie 
all of the tissue of the sporangium has been absorbed fo th 
mary sac becomes shriveled and bent. The cells of 
thalli 
