272 BOTANICAL GAZETTE [april 



the placenta, and the ovary wall. The outer integument always 

 extends considerably beyond the inner, even at the maturity of the 

 embryo sac (fig. 10). The sac becomes deeply imbedded in the 

 cells of the nucellus (figs. 9, 10). It is very long, and averages 

 about 5 or 6 /z in thickness. 



The functional megaspore grows considerably (fig, 14) before 

 the first division of its nucleus. The other 3 megaspores disinte- 

 grate, but are visible at least as late as the 4-nucleate stage of the 

 embryo sac as small, dark-staining cells at the micropylar end of the 

 sac (fig. 17). The 2 nuclei resulting from the first division are 

 usually to be found near the respective ends of the sac (fig. 16). 

 In one case observed (fig. 17), however, one nucleus of each pair 

 had moved nearer the center of the sac. That the latter case is 

 exceptional is indicated by the fact that the 8 nuclei formed by 

 the third division lie in 2 groups of 4 each at the respective ends of 

 the sac. Cell division now occurs in the typical way (fig. 15). 

 The synergids are oval in shape and each has a characteristic 

 vacuole below the nucleus. The egg extends farther toward the 

 center of the sac than the synergids. The 3 antipodals are well 

 defined, angular cells, each with a conspicuous vacuole. After 

 cell division is completed, the polar nuclei remain for a time in what 

 seem to be their original positions near the respective ends of the 

 sac (fig. 18). In one case they were found to have 

 the center of the sac (fig. 19), but no case was observed in which 

 they had come in contact with each other previous to fertilization. 

 Mobile wski (13) found no evidence of a fusion of the polar nuclei 

 in E. virgata, which has a typical embryo sac of 8 nuclei. Hegel- 

 maier (6) found no fusion of either male or female nuclei, or of 

 polar nuclei, in E. dulcis. I found no case showing actual fertiliza- 



mo\ 



tion. Fig. 19 shows the antipodal cells and the synergids appar- 



disintegrating 



male 



from that observed by Miss 

 il nuclei are ephemeral anc 



formation 



It is difficult to trace the course of the pollen tubes, should they 

 be present, because of the long cells of the obturator. There seems 



