Box.— Vol. I.] CAMPBELL— SPARGANIUM. 303 



small size of the generative nucleus makes it extremely diffi- 

 cult to detect, and only a few incomplete observations were 

 made on its behavior after entering the sac. In one case (fig. 

 9) a small, deeply stained body was observed within one 

 of the synergidce, and this very probably was one of the 

 generative nuclei on its way to the egg-cell. In another 

 instance (fig. 13) there was visible within the o^^^ a small 

 body looking like a nucleus, but not staining as deeply as 

 might have been expected of the male pronucleus. In the 

 same preparation (fig. 14) there was a small granular mass 

 attached to the end of the pollen-tube, and looking as if it 

 might have been discharged from it into the cavity of the 

 embryo-sac, but there was nothing to indicate the discharge 

 of the second generative nucleus and its fusion with the 

 endosperm-nucleus as described by Nawaschin ; however, 

 my observations were too incomplete to warrant any posi- 

 tive statement on this point. One of the synergidae can 

 usually be detected for a long time after fertilization has 

 been effected, as has been observed in so many other cases. 

 After fertilization has been effected the egg-cell enlarges 

 very little, and after the membrane is developed about it, it 

 remains unchanged for a long time. At this time the uni- 

 cellular embryo (fig. 24) is a more or less pear-shaped cell, 

 sometimes in contact with the upper wall of the embryo-sac 

 merely by a very small part of the pointed lower end, some- 

 times having a much broader base of attachment. In this 

 condition it remains until the sac has increased a good deal 

 in size and the development of the endosperm is well ad- 

 vanced. Owing to this slow development of the embryo 

 the earlier stages between the unicellular condition and that 

 shown in fig. 37 were missed. 



IV. The Secondary Growth of the Antipodal Cells. 



While the embryo-cell remains unchanged for a long 

 time, the other structures of the embryo-sac undergo marked 

 changes. Almost the first visible result of fertilization 

 is a marked increase in the size of the antipodal cells. In 



