15 



So 92 104 116 1 28 140 152 164 176 il 

 Length in Microns. 



200 212 224 236 



Diagram i. Polygons of variation for length in Culture i and its de- 

 scendants. A and a form together the polygon for 400 specimens taken at 

 random from the original culture i, on April 10, 1907. B, polygon for 100 

 descendants of ten of the larger individuals of Culture i. D, polygon for 

 100 descendants of the single large individual D, from culture i. b, polygon 

 for 100 descendants of fifty smaller individuals from culture i. c, polygon 

 for 100 descendants of the single small individual c, from culture i. 



