648 Davis.—Cytologic a l Studies on Oenothera. II. 
typic division, so that seven split chromosomes enter the resting nucleus of 
the interkinesis between these two mitoses. 
12. The seven split chromosomes may be readily followed as seven 
pairs throughout the period of interkinesis. 
13. The homotypic mitosis is an equation division distributing the 
members of each pair of chromosomes, seven to each daughter nucleus. 
14. The reduction divisions in the ovule result in a row of four cells 
homologous with the pollen tetrad. The embryo sac appears to develop 
rather more frequently from the lowest cell of this row (i. e. the cell farthest 
away from the micropylar end), although often arising from the upper cell. 
15. The vegetative mitoses in the nucellus of the ovule are in all 
essentials similar to those described for the anther of Oenothera grandijlora 
(Davis ’ 09 ). 
Cambridge, Massachusetts, 
April , 1910. 
Literature cited. 
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Farmer, J. B., and Moore, J. E. S. (’ 05 ): On the meiotic phase (reduction division) in animals 
and plants. Quart. Journ. Micr. Sci., xlviii, 1905, p. 489. 
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Overton, J. B. (’ 05 ) : Ueber Reduktionsteilung in den Pollenmutterzellen einiger Dikotylen. 
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