242 



Biology in America 



cliaractors (weip:lit, length, etc.) center around a new mode 

 wliieli is higher or lower than the original. If the character 



(Se /S3 tez 1€6 /69 /7/ /7i /77 130 /B3 /06 I8S fSZ /35B8 



Frequency-polygon and Curve 



Showing variation in height of one thousand Harvard students of 

 ages 18-25. Number of individuals shown by ordinates, and heights 

 (in centimeters) by abscissae. After Castle, "Genetics and Eugenics." 

 By permission of Harvard University Press. 



of each of these groups be plotted, a series of curves is ob- 

 tained, each of which represents "fluctuating" variability of 

 the smaller group and has its owu mode. If all of these 



