1895.) The Emébryo-Sac of Aster. 207 
ing the nucleolus with the nuclear membrane are delicate 
radiating filaments. Fig. 2 represents a typical egg-apparatus 
with its two synergidz and ovum. The large endosperm nu- 
cleus lies just below the egg. 
In tabulating measurements of various features of the em- 
bryo-sac, I was so impressed by the uniformity in the size of 
the nucleoli of the egg-apparatus and secondary nucleus that I 
will give some of the measurements here. The length of the 
mature sac varies from 250 to 3004, its diameter at the egg from 
35 to 454, the diameter of the egg from 22 to 28y, that of 
the egg-nucleus from 10 to 13, and that of the endosperm- 
nucleus from 16 to 204. The nucleoli, however, presented an 
unbroken uniformity, the endosperm-nucleolus measuring al- 
most invariably just 104, the egg-nucleolus 6u, which occa- 
sionally inceased to 7 or 84. The nucleoli of the synergide 
usually measured 4, although in a few cases, they reached a 
diameter of 5 or 6u. 
Development of the antipodal region. 
The uniformity which characterizes the egg-apparatus and 
secondary-nucleus is left behind when we descend to the an- 
tipodal region. For this very reason the antipodal cells of 
Aster Nove-Angli@ furnish an exceptionally interesting 
field for investigation. The text-books would lead us to ex- 
pect just seven cells in the mature embryo-sac, and indeed, 
in the case before us, the sac is often found in this stage, with 
its egg, two synergidae, secondary-nucleus and three antipodal 
cells. But previous to the formation of the secondary- 
nucleus, the antipodal cells frequently enter upon a career of 
development which can hardly fail to attract attention. My 
results here do not agree very well with those of Martin, ? pub- 
lished in this journal. He finds no walls on these cells, 
finds no cross partitions, never finds more than four antipodal 
cells and those never arranged in a single longitudinal row. 
I find that even when there are only three antrpodal cells, 
they form membranes and are usually arranged in a single 
longitudinal row; also that when there are more than three 
antipodal cells, one or more cross partitions are found. 
rom my preparations of Aster and Solidago I should conclude 
that cell walls, cross partitions and longitudinal arrangement 
*Development of the flower and embryo-sac of Aster and Solidago. Botanical 
D. 1892. 
Gazette 17: 406. 
