436 Dr. W. L. Balls and Mr. H. A. Hancock. 



Fig. 13. — Average distribution of convolutions from day to day along the whole length 

 of the hair. Data obtained by taking twenty hairs from the same square milli- 

 metre of one seed chosen at random each day. These hairs, being roughly of the same 

 length, were arranged with their bases in line and the number of convolutions in a 

 1*6 mm. field measured at intervals of successive half millimetres. In five cases, 

 where only twelve hairs were measured, the scale of the distribution curve has been 

 corrected accordingly. The letters a, x and b are placed on some of the curves to 

 indicate the general tendency which appears to be shown, though indistinctly, by 

 the various modes, in shifting backwards towards the base as the date of opening of 

 the capsule becomes later. Base of hair at left hand of each curve. 



