

200 BOTANICAL GAZETTE [hauch 



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amoeba in the chromatin net, mass themselves together as definite 

 individuals, probably in pairs; for thus alone are the later stages of 

 reduction intelligible. 



um 



development. It is therefore of value in helping to determine the 

 exact sequence in the development of the sporocytes. And it is of 

 course evident that if the successive stages cannot be determined 

 with absolute certainty, the whole investigation is vitiated. 



After the development of the chromatin masses, they seem to 

 elongate, as is shown to some extent in fig. 3, and more perfectly in 

 fig- 4. Finally they are stretched out into a very long and delicate 

 continuous spirem, with rather uniformly distributed chromatin 

 granules (fig. 5) . The masses are probably all connected in series and 

 thus elongate into a continuous delicate strand. 



If the individuality of the chromosome is admitted, we may conceive 

 the influence which causes paternal and maternal chromosomes to 

 conjugate in pairs in reduction to be of much the same character a 

 that which induces cells to develop as male and female gametes with 

 subsequent union. This property may develop in the chromosome- 

 only at the reduction stage, and if this were the case, the paternal 

 and maternal units might be indifferent in regard to each other dur- 

 ing all the vegetative divisions. The evidence on this point must 

 come from normal crosses rather than from hybrids, where the two 

 chromatins may have such a lack of affinity as not to conjugate at all. 



spendence of the maternal and paternal chromatin observed in 



first 



But if the individual chromatin masses are distinct in normal vegetative 

 divisions, the pairing may nevertheless certainly take place at the 

 formation of the protochromosomes. It may be well to insist here that 

 the great extension, branching, and change of shape of the chromosome 

 in the resting nucleus does not necessarily impair its individuality. 

 We may reasonably consider the chromosomes to be individualized 



bodie 



Hydrodicty 



which develop various properties at definite times to take them 

 through their life cycle. They have a definite form 



recurs 



^ - — ~ ^v. iV .. Ajucy nave a. ueimuc iwi"i . ff 



from generation to generation, but this is lost during the resting 



