VIIl] 



OF THE GROWING POINT 



635 



any other flattened disc, namely into four quadrants, and afterwards 

 by anticlines and periclines in the usual way. A section across the 

 cyhnder, then, will tend to shew us precisely the same arrangements 

 as we have already so fully studied in connection with the typical 

 division of a circular cell into quadrants, and of these quadrants 

 into triangular and quadrangular portions, and so on. 



But there are other possibilities to be considered, in regard to 

 the mode of division of the elongating quasi-cylindrical portion, as 

 it gradually develops out of the growing and bulging quadrantal 

 cell; for the manner in which this latter cell divides will simply 

 depend upon the form it has assumed before each successive act 



Fig. 280. Diagrammatic, or hypothetical, result of asymmetrical growth. 



of division takes place, that is to say upon the ratio between its 

 rate of growth and the frequency of its successive divisions. For, 

 as we have already seen, if the growing cell attain a markedly 

 oblong or cylindrical form before division ensues, then the partition 

 will arise transversely to the long axis; if it be but a httle more 

 than a hemisphere, it will divide by an oblique partition; and if 

 it be less than a hemisphere (as it may come to be after successive 

 transverse divisions) it will divide by a vertical partition, that is 

 to say by one coinciding with its axis of growth. An immense 

 number of permutations and combinations may arise in this way, 

 and we must confine our illustrations to a small number of cases. 

 The important thing is not so much to trace out the various 

 conformations which may arise, but to grasp the fundamental 

 principle: which is, that the forces which dominate the form of 



