82 COMPARATIVE EMBRYOLOGY OF THE RUBIACEAE 
divisions of the supernumerary megaspores have not been ob- 
served in any other genus, and in all probability do not take place. 
It would appear from comparative study that the large size of the 
megaspores and the absence of compression by the surrounding 
tissues offer favorable conditions for the access of food materials 
and the equally rapid development of all the daughter and grand- 
daughter cells, thus giving them an equal start as embryo-sac 
cells. The embryo-sac cell which finds itself in the most favorable 
position as regards the micropylar canal then commences a more 
rapid development, which takes place at the expense of the remain- 
ing megaspores. In the prophases of the third and succeeding 
divisions the chromosomes are about twice as long as those in the 
second division, the fibers are usually attached at about their 
middle point, where they are bent at a slight angle; the angle is 
directed toward the center of the spindle (pl. rz, figs. 27, 30). 
This division conforms, therefore, to the ordinary vegetative or 
typical division, differing only in the possession of the reduced 
number of chromosomes, which have been determined to be in 
Crucianella ten. It is not necessary for our present purpose to 
describe the remaining divisions in detail, more than to say that 
they fully correspond in character to the third. 
The embryo-sac divisions in Asperula were not studied. 
SUMMARY AND CONCLUSIONS 
1. During the growth of the embryo-sac-mother-cell before the 
first division a large number of coarse fibers are present in the cyto- 
plasm which persist through diakinesis of the first division. These 
are, in part at least, continuous with the circumnuclear complex of 
fibers preceding the formation of the spindle, and do not result from 
a rearrangement of the cytoplasmic reticulum. Further it is sug- 
gested that they be interpreted as currents of kinoplasm (hyalo- 
plasm) corresponding to the radiations described by Wilson as oc- 
curring in the sea-urchin egg. 
2. The spindle in both pollen- and embryo-sac-mother-cell is 
of multipolar origin. The nucleus is at first surrounded by a felt- 
work of curved tangentially placed fibers which gradually segre- 
gate into conical groups. By fusion of these groups a bipolar 
spindle is formed. 
