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1897 | LIFE HISTORY OF LILIUM PHILADELPHICUM 431 
ACCOUNT OF INVESTIGATION. 
In the young nucellus of L. Philadelphicum the archesporial cell 
soon shows its nature by a difference in size and staining reac- 
tion. As is well known, this cell in Lilium develops directly 
into the fertile macrospore, without cutting off a tapetal cell or 
dividing further into a number of macrospores. This gives an 
especially long period of growth for the development of the 
reduction nucleus. After the macrospore has attained some size 
its nucleus shows several large nucleoli, usually three in number, 
with the chromatin rather uniformly distributed and in close 
connection with the nucleoli. Whether the threads of the net- 
work really anastomose or not it would be difficult to determine, 
but such is the appearance. The threads contain numerous 
single chromatin granules which are arranged quite regularly, 
but are not all of the same size (jigs. 1, 7a). 
The chromatin network soon begins to thicken, and the 
granules grow larger, giving the nucleus a coarser appearance 
than in the earlier stages. The nucleoli at this stage usually 
have a homogeneous outer layer, while in the center is a large 
_ Sranular vacuole (figs. 2, 2a, 3). At the time when the integu- 
ments are just beginning to appear as minute projections on the 
side of the nucellus, the linin thread of the chromatin network 
becomes very thick and broad, and the chromatin granules 
undergo transverse divisions, making the whole network with 
double rows of chromatin granules instead of the former single 
row (jigs. 4, ga). At this stage, also, the whole chromatin band 
appears definitely to form a single continuous skein or spirem. 
At the same time, and even before, important changes are going 
on in the nucleoli. Sometimes these are of enormous size, with 
_ @ great granular vacuole in the center. The nucleolus shown in 
Jig. 5 is larger than the average nucleus of the ovary tissue. In 
one case (fig. 6) such a nucleolus was found with a deep dent 
: on one side. Whether or not this was caused by mechanical 
oy injury during preparation it is, of course, impossible to tell. The 
dent in this nucleolus may be of the same nature as the distor- _ 
_ tions which produce the so called ‘‘sickle stage,” but here the 
