26 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



to some distance below the archegonia, then bores in at 

 the side and comes up through the base of the egg. 

 Occasionally it bores down through the jacket cells 

 between the archegonia and then enters the egg from the 

 side. 



Whatever route be taken, immediately the nuclei 

 come into contact the wall of the egg nucleus is pushed 

 in by the male gamete, until it becomes embedded flush 

 with the surface of the female gamete. At the moment of 

 contact, both nuclei shrink somewhat, a process which 

 stops when fusion is complete ; with other changes both 

 nuclear walls disappear, and a spindle bearing 24 chromo- 

 somes is in evidence (tig. 13). The changes which take 

 place in the interval between the embedding of the male 

 gamete in the substance of the female gamete, and the 

 presence of a spindle with chromosomes, are, according to 

 all investigators, of a very remarkable and complex 

 character. It is stated that no resting nucleus is formed, 

 that the two nuclei pass independently into the spirem 

 stage, and that it is only when on the spindle that the two 

 groups of chromosomes become fused. 



Margaret C. Ferguson describes in great detail the 

 course taken in Pinus strobus for this interval, and gives 

 21 figures in illustration. From her very abundant and 

 rich material she has selected a series of figures that 

 certainly appear to follow each other in admirable 

 sequence. In my poorer material — for there is in Miss 

 Ferguson's work evidence of a far larger proportion of 

 fertilised eggs than in that at my disposal — I have been 

 unable to discover but a few phases that may possibly 

 represent stages of development during this particular 

 interval. None of them are in any way similar to those 

 figured by her, and I am inclined to regard some of them 

 at least as being abnormal. A wisp-like stage somewhat 



