138 MARGARET C. FERGUSON 



cell, since it lies in the cytoplasm of a cell which supplies the 

 most favorable medium for growth found in the plant. Not the 

 slightest evidence has been observed during this research that 

 the nucleus of the ventral canal-cell ever divides or that it ever 

 conjugates either with the egg-nucleus or with the smaller 

 sperm-nucleus. The fact that this nucleus enlarges when fed 

 by the cytoplasm of the egg does not seem to me conclusive 

 evidence that it has been "organized as an egg," as stated b}'' 

 Coulter and Chamberlain ('01). The tube-nucleus and the 

 smaller sperm-nucleus often enlarge after their entrance into 

 the egg but, surely, they are not thereby changed into eggs. 



The fragmentation of the egg-nucleus has been observed sev- 

 eral times and is illustrated in fig. 270. The ventral canal-cell 

 can still be seen just above the egg. Such fragmentation of the 

 egg-nucleus is not rare in the Gymnosperms having been re- 

 ported by various writers. 



In one instance one of the two segementation-nuclei was 

 found to have divided while the other remained undivided. The 

 undivided nucleus had increased much in size and contained 

 seven large, granular spheres distributed on an achromatic re- 

 ticulum. The nucleus is evidently in a state of disintegration 

 and these spheres probably represent granular masses of chro- 

 matin (fig. 274). 



A Peculiar Method of Conjugation. — Of all the irregular or 

 abnormal developments observed that illustrated in fig. 275 is, 

 to me, the most interesting. A pollen-tube has conjugated with 

 an egg, not through the normal passage formed by the neck- 

 cells, but has forced its way through the sheath-cells at one 

 side of the archegonium. Impregnation has evidently followed 

 and division has taken place as usual, four nuclei of the pro- 

 embryo having been formed. 



The fifth large nucleus shown within the egg is doubtless the 

 smaller sperm-nucleus. The open space separating the upper 

 part of the prothallium from the nucellar cap has evidently not 

 arisen as a result of shrinkage during fixation. The pollen- 

 tube unable to span the opening has turned aside and finding a 

 point at which the endosperm and nucellus were in contact it 

 has entered the prothallium and made its way along the side 



