Variation in Portiinus depurator. 



227 



and so the generalised probability curve would be one of unlimited 

 range. 



R. Antero-lateral. The mean fluctuates considerably in the different 

 groups, but there is a slight tendency to fall. Omitting the first 

 group as being too small, it will be seen the mean falls about one 

 unit in the whole series. 



Range of deviation = 732 831 thousandths of standard, giving 

 25 units of variation. We select groups 6 12 (1432 individuals) for 

 forming a frequency curve. Here the range = 736 819 thousandths, 

 giving 21 units. 



FIG. 3. B. Antero-lateral. 1432 Individuals (see fig 2). 



Centroid = H'331704. p* = 9 296165. 



ff = 3-048978. /IB = -1-075979. 



/*4 = 255-659399. 

 ft, = 0-001441. fa = 2-958381. 



r = - 6 (^ A" 1 ) - 134-096687. 



3/^-2/32+6 

 Skewness = 





= 0'01955. 



