IV] AND STRUCTURE OF THE CELL 317 



which give rise to the appearance of rays, or striae, around the 

 nucleus: and through increasing diffusion and weakening surface- 

 tension the rounded outHne of the nucleus finally disappears. 



As we study these manifold phenomena in the individual cases 

 of particular plants and animals, we recognise a close identity of 

 type coupled with almost endless variation of specific detail; and 



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^»N f" % 



o a o 1 ^ ^ 



(I V J * /•v • 



V 



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lOj 



0. 





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Fig. 96. Various numbers of chromosomes in the equatorial plate: the ring- 

 diagrams give the arrangements predicted by theory. From Graham Cannon. 



in particular, the order of succession in which certain of the pheno- 

 mena occur is variable and irregular. The precise order of the 

 phenomena, the tiiiie of longitudinal and of transverse fission of 

 the chromatin thread, of the break-up of the nuclear wall, and so 

 forth, will depend upon various minor contingencies and ''inter- 

 ferences." And it is worthy of particular note that these variations 

 in the order of events and in other subordinate details, while 



