50 



CELL-DIVISION AND GROWTH 



II. i 



as would have been produced by an equal following on an unequal 

 division, the four surfaces meeting in one line as before (Fig. 26 

 E, F). The appearance presented is like a side view of a radially 



JL c, 



FIG. 27. Arrangement of four oil-drops produced by unequal division of 

 two equal drops, the small and large drops alternating. The first division 

 is shown by /: the second (II) may pass as in a or in b, but the result is 

 always as in c, the two large drops meeting in a polar furrow and excluding 

 the small drops from the centre; the system is symmetrical (iso-bilateral) 

 about the dotted lines in c. (After Roux, from Korschelt and Heider.) 



segmenting egg after the third division. When, however, the 

 smaller drops were not adjacent, but opposite, five surfaces of con- 

 tact were formed, 

 a polar furrow 

 appearing between 

 the two larger and 

 joining the centres 

 of mass of the 

 two smaller drops, 

 whether these are 

 unequal or not. 

 The direction in 

 which the division 

 of the drops is per- 

 formed is irrelevant; 

 the final result is 

 always the same. 

 Should two adjacent 

 drops be equal, the 

 polar furrow is still 

 formed by the union 



FIG. 28. A and B are diagrams of an oil-drop 

 divided into four and eight to explain Roux's 

 notation. Cis a figure of the oil-drop divided into 

 eight equal parts. (From Korschelt and Heider.) 



of those two which have together the larger mass (Fig. 27). 



