GENETIC TYPE AND THE ENDOCRINES 317 



than statistical averages in the study of characters exhibited 

 by F 2 hybrids thus the important value of the above review 

 of these charts for individual indices. It might be mentioned 

 in this connection that most human individuals are of at 

 least the second generation in regard to almost all their 

 separate features and characters, and that they therefore do 

 not lend themselves to a reduction to community averages in 

 any effort which might be made to properly understand the 

 given characters and tendencies among them. With this in 

 mind we shall return to a further brief consideration of the 

 individual animals in the F2 and backcross hybrid generations 

 between the bulldog and the bassethound. 



A second arrangement of curves may serve to bring out 

 the individual differences in the same series of indices and 

 proportions. In text-figures 70 and 71, the range of the char- 

 acters in three bassethound skulls is represented by the 

 area in solid horizontal lines. The range of values for the 

 same characters in twelve bulldog skulls is shown by the 

 dotted area enclosed in dash-dot outline. In text-figure 71, 

 the range for three F x skulls is plotted in solid black, and 

 in both figures the range in values for thirty F2 skulls is 

 represented by the area in dashed horizontal lines. The char- 

 acters concerned are again listed at the bottom of the figures, 

 each being immediately below the place on the curve which 

 represents its value. Although the individual deviations from 

 the average are represented in this pattern of curves, yet 

 the skull characters concerned are so complex in their com- 

 position that the range of the F 2 hybrids fails to either reach 

 or overlap the parent ranges for those characters which are 

 highly contrasted in the two parent skull types. The snout 

 index of the bulldog, for example, would seem to involve so 

 extensive a complex of hereditary factors that extremely 

 large numbers of F 2 animals would be needed to furnish 

 the chance recovery of the exact genetic combination which 

 is necessary to induce its fully expressed condition. In spite 

 of some discouragement to w r hich these curves may give rise 



