212 The Botanical Gazette. [May, 
2. (a) The egg is sometimes spherical and sometimes pear- 
shaped. 
(6) The vacuoles and nuclei of the synergidz vary in posi- 
(c) There isa striking uniformity in the size of the nucle- 
oli of the egg-apparatus and the endosperm-nucleus. 
3. (a) The number of antipodal cells varies from two to thir- 
een. Six or seven are as frequent numbers as three. 
(6) The number of nuclei in an antipodal cell varies from 
one to over twent k 
(¢) The lower antipodal cell differs from the rest in size, 
density of its protoplasm, appearance of its nuclei, 
and in its effect upon the surrounding tissues. 
4. The discovery of an antipodal odsphere in the antipo- 
al region is an additional proof that the antipodal 
cells are homologous with the endosperm of the 
gymnosperms, : 
Acknowledgements are due Dr. John M. Coulter for his 
kindly encouragement and valuable suggestions during these 
researches. 
University of Chicago. 
EXPLANATION OF PLATES XV anp XVI. 
All figures are drawn from sections of the embryo-sac of Aster Wova- 
Anglia and are magnified 407 diameters. 
Abbreviations—ao, antipodal odsphere. en, endosperm nucleus. 
fa, lower antipodal cell. m, micropyle. 0, odsphere. on, nucleus of 
odsphere. fv, polar nucleus. sy, synergidae. 7, tapetal cells. 44, 
upper antipodal cell. : 
Description of figures.— Figs. 1 and 2. Sections through the entire 
embryo-sac. 7 i i 
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